Full text of "Mathematical collections and translations, in two tomes, [translat. and ed.] by Thomas Salusbury"

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2°K.B. 9,163

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

MATHEMATICAL

Colledions and Tranflations :
In two

TOMES.

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

MATHEMATICAL

COLLECTIONS

AND

TRANSLATIONS.

The first

TOME

THE FIRST PART>

J. Galileus Galileus, His STSTEM E of the
World.

II. Galileus, his ETISTLE to the gKAU^'J)

VUTC HE SSE Mother condllmim the Juthority of
Sacred Sdil'PTUI^E iriThyloffl^md QoritrGverfies.

III. Johannes Kepler us, his 'J^e.conCilim of SC\[-

TTWR^E Texts, &c.

IV. DiDAcus a Stunica, his 'Reconcilin^s of SCRl-

^^rU'JiE Texts, &c.

sgari n u s,hts Epijlle to Father F^dKCTO^AC^llS,
reconciling, the Juthorityof Sacred SC^ ITTUR E ^
and fHdgments of 'DiVines alledzed a^ainjt, &c.

By THOMAS SA LUST>Ul{r, Bfq.

LONDON,

Printed by W I L L i A M L e Y b our n e , mdclx i.

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

To the Noble and moft perfedly Accomplifhed

S'JOHN DENHAM

Knight of the Noble Order of the

BATH,

And Surveyor General of his Ma"" Works, &c.

Sir 3

Humbly begge your Pardon for
bringing this Book under your Pro-
tection. Were it a Work of my
o wn>6r I any thing but the Tranfla-
tour^I should mafter my Thoughts to a meaner
Dedication,* But being a Colledion of fome of
the greateft Matters in the V Vorld,and never
made EngHsh till now , I conceived I might
fooner procure their Welcome to a perfon fo
eminent for Noble Candor , as well as for all
thofe Intelledual Excellencies wherewith
Your Rich Soul is known to be furnished. I
refolvd to be as kind to this Book as I could,

and

and ferioufly confidering which way to efFect
it , I at laft concluded to prefix Your Name,
whom His Majefty and all his Subjedis^ (who
have a higher Senfe and Judgement of Excel-
lent Parts) know beft able to defend my Im-
perfections. And yet I confefs there^s one
thing makes againfh me? which is your eminent
Integrity and great AlFe6bion to Truth, where-
by my Lapfesin a Work ofthis Nature might
j ullly defpair of Shelter , butithat the Excel-
lency of Your Native Candor ftrives for Pre-
dominancy over all Your great Abilities. For
^tis all-moll impoflible to think what Your
Matchlefs V Vitisnot ableto Conquer,would
Your known iViodefty but give leave: there-
fore Gal/kus^Kep/er 4M'thok other Worthies
in Learning are now brought before You in
English Habit ; having changd their Latine,
Italian and Frencji,whereby t:h^y werealmoft
Strangers to our Natibn,unlefs tb fuch'is Yotij'
who fo perfedly maftcr the Original^^¥know
you have fo much and great imployrtieht fof
His Majelly and his good 5ubje£tstfiafi shall;
not robb you of another Minutes lofs ;^bdid^^'
the liberty of fubfcribiiig my Self ; ^'fi-3nim3

, Moft Mumble ;
Moft obedient Servant

THOMAS SALUSBURY.

READER,

}

f70t to

ZlhJ^^c. thai had bin fo lately emft led by the hand of ''^'''''''r^^^^^ time drawn

jZLZlon'hereofthe Sums that a Loyal Refle... ^r^^/^^^^^^^^

Tom me; and judo^d that the mo^ fafe, eafy^, and ^^f;J^^^^^^ ,,Lrd/the charge of th. P.-

deryrom of the Book^.to be contrtbHtary totheir ownComntment , byjut^jcrw ^

yilcation.

-'^rrEncourajreme.tfromthatpM^^^^^^

more than common Ajjifla

Trofefion in thBHfinefs. ^ Encouragement jrom y^^..^^^- - - y

rA/i ^J'-'^'^^^g ^^rlo^ ^ ProvoJTof .:^ec»i f^cu^^ ^-c^.A, Mai gave: Prof fj/'^^- -
l^earned Dr ^Mathematicians and my %ealLFr,e»ds ^jr^j^r Miles Symner, (

^ /ffi'r/ffi^^ ^'^''^ "^^^ U^W./,.... ^.l^d me a concealment

of their ^ames.

^The names of thofe Anthorsani I ""'^'"' Trr^. J. ^ 7^^^,,^ Dlfil^Ei Tomes they are as conffiing of
feveral pieces : Collettions I cm j „ot pretending to ar,j ihing more than

hereafter g.v. you ^'^'Sf in Italy (fj he c.L, hm Uve he.rd that though ,hp have

whr thefe Diahgues fouKl I" vanousenuna.nm ,J-^;.^ y,erc w th mufb detefiattoii perfected,

{Li .rJ S^grcdo the 7^^^^ « ban the_ V I jlM,^ his Ho-

mer Simplicius to perfoMte the {'"P''!'"'^^ .-^ ^ivl In iecU!>»,ng a.atnSt the Sam.an T>hUo.

,ourto i'concer.-d-^h^'''S!^«l'.-^ ~hU Argument, , and pur

fovhr, ""i "'^ hefupfoled) he.nr ,11 del w.thhy ''''""^f^^^f '^'^^^ D-JpleafureagahHcur ^u-

' L^hto the mouth ^fSimplicius; V^'«'^'«r" - ' "G^^

■with the Conpflori

thor,andthhl^.g.o other revenge fuffaent^^^^^^^

to condemn hm and p'ofcnk his B>.k'''Heret.cal;proptmng theU"J^ ^ ^ .^^ ^^^^ ^/-^^.^^^^^ _ ^Jf,^

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

Tft'ifcarrUge of the unfortuytate MathiasBemeggeius who firfi attempted to turn them wt» Lattne for the henefU
vf the Le^irned H'orld. ^
I (hall not pre fume to Cenfttre the Qenfure which the Church of Rome pafi upon this DoElrlne and Its yljfertors
Button the contrary, my Author having h'ln indefinite In his dlfcourfe , I fl, all forbear to exafperate, and attempt
to reconcile [uch perfons to this Hypothefls as devout efieemfor Holy Scripture , and dutifull RefpeO: to Canonical
InjunUtons hath made tofland off from this Opinion : and therefore for their fakes I have at the end of the Dla
logues by way of fupplemetit added an Eplfile Galileo to Her Moil; Serene Hlghnefs Chriftina Lothalint^a the
Grand Dutchefje Mother o/Tufcany ; as alfo certain Ahjlracls <f John Kepler , Mathematician to two Empe
rours^ and Didaciisa Sinmc^ a famous Divine of Salamanca^wlth an Epijlle 0/ Paulo Antoiuo Fofcaiini a learn
ed Carmelite of Naples, that'jhew the Authority of Sacred Scripture In determining of Phllofpphlcal and Natu
ralControverfies '.hoping that the tngeniom & impartial Reader will meet with full fatisfaUlon In the fa e
ay^nd leajl what I have fpoken of the prohibiting of thefe Pieces by the Inquljltlon may deterre any fcruiuTous
perfonfrom reading of them , / have purpofely Inferted the Imprimatur by which that Office licenced them And.
for a larger account of the Book, or Author, I refer you to the Relation of his Life, which Mbrln^ ut> the R.ar^
m the Secovd Tome. s f <^

concerning
tende,

icmiv^f ^oiuni. ^ome may aueage, ana 1 doe confejs that 1 promijed to pubhfij the Life of Galileo this llace
But the great mlfcamages of Letters from fome Friends In Italy and elfe where , to whom lama Debtor f rf
veral Remarcfues^c^^ from whom J dally expeByet greater Helps concerning the Hlfiory of that famous P ConaJ'-
thefe dlfappolntmentsjfavjoyned with the undeniable Re^uefi of fome Friends, who were Impatient to felcMU
in Englifio , together with a confideration of the dlfproportlonate Bulkjhat would otherwlfe hive bin betwixt the
two J>^o/umes,perf waded me to this exchange. This deviation from Promlfe I hope is Fenlal zr, ^ f v ./ ^ . v
piatingofitlplead Supererrogatlon : having In each Tome made fo large Adltlons (thoud to Z,^^^^^^^
l^liltl ^^KT^' ^'.'i'.' PMjh.That thif'sfl^ffJppLr^^^

I them with the refi : a»d hope that ifyyu f^/«A- • '^>^ve done therein worth your acknajvledo-a

mem , you wjltyet at leafl account th^ ^ncreaje of my expence a fufficlent extenuation of the TrefpafjtlUa
Additions have forced me tn mi^^it ptponyoar Patience In point of Time. ^ tnofe

zAsfor the fecond Tome, I have only this to affure the Generous Reader s\ i that I am very conftd t T fL n
be much more punBual in publifhln^ that, than (for the reafons above related:) I was able to be lnhtlTn f U

thelVorld.

To fay nothing; of the dlf advantages of Tranflations in Zf»eraU this n^*yi',-^i> J. i.r r • - ,
roUald overffghts : but thofe of the T>rlnteJ dlf counted, nop he jiTfe ttf ""I^T
n.an i.-..^\Atxhetr.this,l hive affumedthe Liberty I Jcthe Mifi"^^^^^^^^

rus In the Margent, not fo much to reproach him , as to convince thofe who told r»e tl,^, //^ ^^-''''^ beinegge-
needlefs,having his Latine Tranfiatlon iy them.The like they f aid of the whole two ToZ IZ ""I'^'^f'^r^y P^'"^
me to qnenlon their Underfianding or Veraclty.F or fome of the Books were yet never evtan! A fV'''''^''^
the Mechanlcks of Monjieur Des Cartes , a Manufcrlpt which I found amongfi the many other RarY '
'ch the welUhofen Library of my Learned and fTorthy Friend i>r.Charlcs Scarbui'^h- the Evn^riL '^^ ^^fJ""'
ity.and the Life of r;;iIilro. both own : Others wen- l^rfarl^^ T^.l... ^JiA • ' . .f!^^^ "f ^^'«-

nis xjiaiogues ae Motu; {^never till now aone into anji j^anguage) which were jo mtermixt of Lai I ne and It r
that the difficulty of the Stile, joyned with the Intricatnejfe of the SubjeB rendered them Unpleafant if-^ot lu't^
Vnintelllgible, tofuch as were not ^bfolute Mafters of both the Tongues. ^ ^"'^^^

To conclude- according to the entertainment that you p leaf e to afford thefe ColUaions,! fir all be encouratreJ t
proceed with the Publication of a large Body of Hydrography-declaring the Hlfiory, Art, Lawes, andApendaZ
of that I rincely Study of Navigation, wherein I have omitted nothing of note that can be found either i„ TUA
ley, Fournier, Aurioarius, Nonius, Sncllus, Marfcnnus, Bayfius , Morifetus, Hlondus , Wagoner , abroad or leaTr
amongn our Mariners at home, touching the Office of an Admiral, Commander, Pllot,CModellHl Shlvwrlcrhr
gunner, ' i &"^y

But order requiring that F fi>ould dlfcharge my firfi Obligation before I contra^ a fecond: I (hall detelr you
longer in the Portall,bHtput you intopojfejjfiottof the Premlfes^ '«7f«^#

JSlovemb. 20. 1661,

THE

ifertors.
attempt

if 2>/W-
nga the
Empe-

t learn-
I Natu^
• fame.

n. AnA

>e Rears

Moyfio,
'ttperiM-
' place :
rforfe-
•fonage:
Caftelli
nxt the
the ex.
•eat ex~
ppearby
'.pltomes
time of
'yafup-
nts that

y °fpf*'

nvtedge-
<it thofe

tifhall
gforth
'felling
eans a-
^es into

t's Er.
ofHu.
rneg^e-
fjf pains
caufed
fiance ;
hat en^

ed that
^echa-
h' notes
irve all
tallan^
Jfbplly

SYSTEME

OF THE

WORLD:

IN FOUR

DIALOGUES

Wherein the Two

GRAND SYSTEMES

Oi 0 LO MY and COl" E ^(^^ ICU S

are largely difcourfed of ;

And the 1{EJS0 both "Phylofophical and Thy fa ah
as well on the one fide as the other, impartially
and indejinitely propounded ;

By qjLlLEUS QALILEUS LIU^CEUS.
A (jemleman of ELO%E^Ce : Extraordinary Trofefor of

the Unthematicks in the N I V E R S I T Y ot T I S A and
Chief Mathematicianto the GRAND DUKE of TV SCANT.

Uglified from the Original Italian Copy, hy THOMAS S ALU S B U RY.

A L C I N O li S J

S 1 N E C A ,

/«/«■ mllos magit qnm inter pHl LOSOPMOS effi debet a^ia tIBeRTAS.

LONDON,
Printed by WILLIAM LEYBOUaNE. P^DCLXL

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

To the moft Serene Grand Duke

o F

T US C A N Y.

Hough the difference between Men and other
living Greaturcs be very great, yet happly iie that
fiiould fay that hecouIc| ftiew httle lets between
jUari and Man would not Ipeafc marc than he
llg^Uf^si^ might prove- What proportion doth one bear to
athoufand > and yet it is a common Proverb , Ofie zPlfan is
mrth Athoufand, yphen as a thqufand are not mrth one. This difference
hatK dependence upon the different abiUties of their intelle-
«auais i . ^vhich I reduce to the being , or not being a Philofo-
pheri ih regard that Philofophy as being the proper food of
liich asUveby itydiftinguifheth a Man from the common
fence of the Vulgarin a more or lefs honourable degree accord-
ing to the variety of that diet. In this fence he that hath the
highefl looks, is of higheft quality ; and the turning over of
the gr^^t Volume of Nature , which is *he proper Objedl of
Philofophy is the way t6 make one look high; in which Book,
although whatfoever we read , as being the Work of Al-
mighty God , is therefore moil: proportionate yet notwith-
flanding that is more abfolute and noble wherciif we more
plainly deferne his art and skill. The ConHitution of the Vmvers,
amoiig allPhyfical points that fall within Humane Compre-
henfion,may;in my opinion, be preferred to the Precedency
for if that in regard of univerfal extent it excell all others , it
ouaht as the "Rule and Standard of the reft to gee before
them in Nobility. Now if ever any pcrfons might challenge
ie be fi^nally diflinsjuifhcd for Intelledfuals from other men/
^ J ^ ■ • Tib ? ■

Ttokmey and (Jopernicus were they that have had the honour to
fee fartheft into, and difcourfemoft profoundly of the fforlds
Syflcme. About the Works of which famous Men theft Dia-
lous being chiefly converfant , I conceived it n^y duty to De-
dicate them only to Your Bighnefs. For laying all the weight
upon thefe two , whom I hold to be the Ablefl: Wits that
have left us their Works upon thefe Subjects 3 to avoid a Sole-
cifmein Manners,! was obliged to addrels them to Him, who
with me, is the Greateft of all Men , from whom they can re-
ceive either Glory or Patrociny. And if thefetwoperfbns
havefo farre illuminated my Underftanding as that this my
Book may in a great part be confefled to belong to them , well
may it alfbbe acknowledged to belong to Your HighnefsyXxnto
whofe Bounteous Magnificence I pwe the time andleafiirel
had to write it, as alfounto Your Powerful AfTiflance, (never
weary of honouring me) the means that at length I have had
to publifli it. May Your Htghmfs therefore be pleafed to accept
of it according to Your accuflornedGoodnefs j and if any
thingfhall be found therein, thatmaybefubfervient towards
the information or fatisfadVion of thofe that are Lovers of
Truths let them acknowledge it to bedue to Your Self who are
fo expert in doing good, that Your Happy Dominion can not
fhew the man that is concerned in any of thofe general Cala-
mities thatdiflurb the Worlds fo that Praying for Your Profpe-
rity , andcondnuancein this Your Pious and Laudable Cu-
itome, 1 humbly kifs Your Hands h

Your (t5MoJl Serene Highne^es
Moft Humble and moft devoted
Servant and Subjed

.<3ALlLEO GALILEI.

'to

iDia-
pDe-

Xreight
ts that
I Sole-
^who
can re-
erfons
is my
■well
ninto
lure I
jpever
■had

n-any
wards
ers of
■bare

Ml not
Cala-
rofpe-
; Cu-

THE AUTHOR' S

INTRODUCTION-

Judicious Reader ,

iHerel^aspubtiJhedfom years fince in Komt a falut if erous Edia , that , fir
I the obviating of the dangerous Scandals of the pre/ent K^ge y tmfoftdafea^
I finable Silence upon the Pythagorean Opinion of the Mobility of the Earth,
There Ti>ant not fUch as unadvtfedly affirm .that that Vecree^^as notthc produ-
Bion of a fober Scrutiny of an illtnfirmed Pafsion',& one may hear fomemut-
ter that Con fultors altogether ignorant of yifironomicalObfervations ought not
clipp the vVingS of SpecuUttve Wits 'Wri^ ra/h Prohibitions. <JMy ^tale cmn-
noTkee filef^^^^^* ^ ^^^^ t^eje t„uuf,jft^t>rHt» Jt ihvw^ht p't^ tct bcingthoroughly aC"

"quaintedlfiiththat prudent Determination, te appear openly upon the Theatre of thtWorld as a Wtt~
nefs of the naked Truth. I Ivas at that time m Rome-, and had not only the audiences , but applauds of
themoft Eminent Prelates of that Court',norl»as that Decree PubLfhedTt^ithout Previous Nottcegiven
me thereof Therefore it ts my refolution in theprefent cajt to give Foratgn T^ations to fee , that this
point is as-^ellunderHoodtn Italy , and^arttcularly tnKom^ ,asTranfilptmDtligencecanimagine
it to be ' and coUeOing together all the proper Speculations that concern the Copernican Sy ftcmc,
to let them kno-^.that the notice of all preceded the Cenfure of the Roman Court 5 aMat there
proceed from this Climate not only DoBrtnes fir the health of the Soul, but al/o tngentous Dtfcovenes
for the recreating ef the CMind. r 1 1 r

To this end i have per fonmd the Copernican in this Difcourfe j proceeding upon an Hypothecs
purely CHathematical-Jriving by allaitifictallfiayes to reprefint it Supertour, not to that of the Im-
mobility of the Earth abfolutely, but according as it is mtnttonedby fome , that retetn no more, but the
name (^/-Peripateticks . and are content, T^ithout going farther ,to adore ShadoT^s not phtlofophii.ing
T^ith requifit caution, but mth the file remembrance of four Principles, but badly undoftood

We flo all treat of three princtpall heads. Ftrfi 1 loill endeavour tofheTV that all Experiments that can
he made upon the Earth are infufficient means to conclude it's Mobility, but are indifferently applicable
to the Earth moveable or immoveable : and J hope that on this occafion T^efhall difiover many obfir-
vable Pajfa^es unknolt^n to the K^ncients. Secondly T»e "SPtll examine the CosLefttall Phc3enomcna
that make for the Co^ctmcm \{y^o\hc^is,asifitl^eretoproveabfolutely vtBorious', adding by the
T^ay certain neT^ obfervations , l^hichyet ferve only for the ^ftronomtcal Facility , not for Natural
Necefity. In the third place I l^illpropofi an ingenuous Fancy. I remember thnt 1 have f aid many
years fince. that theunknol^nProblemeofthe Tide mtght receive orne light admitting the Earths
LMotion. This Pofitionofmine pafsing from one to another had mid charitable Fathers that
adopted it for the Ijfue of their oT^n T»it.NoT^,becaufi no ftr anger mny ever appear that defending him-
felhtth our armes.fhall charq^t us l^tth l^ant of caution in fi principal an ^cctdent,I have thought
Jod to lay doipn thofe probabilities that 1»ould render it credible , admitting that the Earth did
mo've I hope, that by thefe Con f derations the World >/// come to kno-^ , that if other T^ations have
Naviaatedmorethan-^clpe have notfiudiedlefithanthey',& that ourreturnmg to afftrt the Earths
Stability, and to take the contrary only fir a Mathematical Cz^nccio, proceeds not from tn^dvertency
of T^hit others have thought thereof , but (had l^e mother inducements) from thofiReafons thatPtc^
ty,Reltgton,the Knoi^ledgcoftheDivintOmnipotency y andaconfitoufnefe of the incapacity of mans

VttderJlAnding diciate unto us, ^ ^

With

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

im.a I conceived it v(,y proper U exprefi theficcncemby T^,y ofvUlcgne, a.„ot bd',

/ometimisnelefscurKimthanthe principal x^rgument. ^ ' """"" 're

I chanced tohcf-veralycarsfirue, atfiverat ttma. m the S,upe„diom Citty of Venice T,hre I

c^methuher from Borence at ihefame time Signoxef MppoSaWhti itUr hln^l., ^ \.

.nj flcafire than on elevated SpecuUtLs. „ the ~ny of theTUA^^^^^^^

matters b, fore a certatn fer,pLick Phtlofopher y'hoJeLLIhavc n l'jJZi^^^^^^^

ing of the Truth, than theJan.e hehadacqitredhy ^r,ftot,ltcd iZKtlljl '""^"fi^nd-

No-\>, feeing that inexorable Heath hath deprived Venice and Florence o1 thofe it,o a,,., r:.L. ■
the very <^cr,d.an of thetr years, ld.drefLe, asfar ^my poor ab.l.ty-^luutl^^^^^^^
'hetrl,vestothetrhonour>nthefeleavesJr,.gtngkrninL^M^^

Korjh. lithe HoneH Peripatetick T^ani his plate, to T^hom for his excefsive Jff'm! ,Z ^'"'['^"'fy-
'ner>tartesofi\mp\xtxxx%Jthoughtfit,T>ithomrnentioninghisoT»nNar>,eJu^^^
hefor^uchrelpeaed. Let thofe ,^,o great Souls .ever venerd,le to rny hem pU^^^^^
blick CMonument of my never-dytngLove ; andlet the rernernbrance of their pLZT'^r'^"
delivering to Pojlertty the Confiderations that 1 have fromifed. ''io'[«ence afstfl mem

There cafrally happened (m Tt^as ufmtl) ftverat difcourfes at times betlteen th,n r- i l
1»h,cb had rather inflamed than faiisfied tn their T^us the thirfl they haZ l I ' ^""^'f"'">
'^^'■-■■---^'''S^''^^^ fir certain dayesU^i^^^^^^^

'^^/^o^icallytoeontempLetheWot^^^^^^^^

they look a dfcreet refoiution to meet together for certain dayes , u T^hiT'n ZrT^r '' '^t'"ff"
theym^ghtbetakethemfelvesmoremethodiJlytoconUmpitethewZderfofr^^^^
t^e Earth: the place appotntedfortheirmetttngheingin the Palaceofthelob^^^^^^
due, but veryfhortcomplemms; Signore Salvifti began inthts m.J^er Sagtedo,-,//.r/*r

GALI-

ich:g

The CONTENTS of the FIRST

TOME

PART THE FIRST.

'Aghtsin
rpetuaie
^rovnfy,
he Com^
yfuthor
this fu-
^ me in

%,the

mupon
'tafide,
^and in
^the

TrtMtife I.
11

III

IT,

lU.

IV.

! V.^
VI.

yn.
yiii-

IX.
X.
XI.

XII.

GALlLEUS GAULEUS,hisSYS *EME of ttcWoRLD : inpour Dialogue
His Epistle to her Serene Hichnesse CHRISTIANA LOTHERlNGA
GRAND DuTCHEssE of TuSC ANY , toiiching the Ancient and Modern
Doctrine of holy Fathers, aniJuDiciots Divine s, concerning
the Authority of sacred Scripture in phylosophical
Controversies.

JOHANNES KEPLER US, his Reconcilings of Texts of sacred
Scripture tbatfccmtooppofctheDocTRiNE of the Earths mobili-
ty : abftraftcdfrom his Introduction unco his learned Com men-
tar ies upon the Planet MARS,

DIDACUS A STUNICA, a learned Spanish divine, hisRECoNCiLiNCs of
the faid DOCTRINE with the Texts of sacred Scripture; abftra6ied
from his Commentarie upon JOB.

PAULUS^ ANTONIUS FOSCARINUS , a Garme lite , his ^ p i s t l e to
SEBASTIaNUS FANTONm, the General of his Order, concerning
the Pythagorean and Gopernican Opinion of the mobility of
THE Earth , and stabii.x±y of the Sun ; and of the nfw Systems
or coNSTi'"'^'^^^ of the World: in wbfcii he rcconcileth the Texts
OP s>..c^ED ScRi p TURE , and As sERTioN s ot Divine s , commonly
alledged again ft 1 u w .

A Table of the most cbfervuble Perfons and Matters in ffe^FifftPart.

^ PART THE SECOND.

D.BENEDICTUS CASTELLUS, ABBot of S. Benedictus Aloysius, his
Discourse of the mensuration of Running Waters : The Firft
Book.

His Letter to GALlLEUS, rcptcfcnting the ftatp of the Lake of Perugia in
Tuscany.

His Geometrical demonstrations of the measure of Runntt^g
Waters.

His discourse of the men suratiOn of Running Waters : The Second

His Con s^id'e rations concerning the Lake of VENICE. In two dts courses.

His Rule for computing the quantity of mud and sand that Land-Floods bring
down to, and leave in the La K E ot VENICE. ^ . .

His LETTERto Father FRANCESCO di S.GIVSEPPE, wherein , at the inftancc
of PRINCE LEOP ALDO,he delivcreth his judgment concerning the turning
FiUM E M oRT o (a River near Pi s a in TUSCANY ) into the Se a , and into
the River Serch lo. .

His fccondLETTER inanfwcrtocertainOBjECTioNs propolcd,ana di f f icul-
TiEs obferved by Signore BARTOLOTTI , in chat affair of the
Divers ION of FiUME morto. n • /-

His Consideration upon the drain in g of th« p on tine hENN s ni CALA-
BRIA ' V

His Consideration upon the draining of the Territories of BOLOG-
NA, FERRARA, and ROMAGNA. .. ^

His Letter to D. FERRANTE CESABJN I, applying his Doctrine to the

MENSURATION of the LEN GT H,and Dl S TRIBUT I ON Of theOJlANTlTY

of the WATERS of Rivers, Springs, Aci:iEDUCT5,8ic.
D CORSINUS, Superintendent of the general drain s, and Pre s iden t
of ROMAGNA, his Relation of the ftarc of the Waters in the
Territories of BOLOGNA and FERRARA.
«^ Table cf the wofi thfervnyit Pcrfons Matters mentioned tn the Second Part.

* 2 The

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2°K.B. 9,163

The CONTENTS of the SECOND

TOME

Trtarife I.

IV.

pART THE FIRST.

r ALILBUS GAl-lLEUS, his mathematical discourses and demon*!
sTRATioMS touching two NEW Sciences, pcrtainingtothc Me CH A*
NICKS, and local motion: with an Appendix ot the Centre of

GRAVITY offomC SOLIDS in FoUl DI A L O CUE S .

Utc MECHANICKS; aNewPEicE. j
u HPN ATUS De s CARTES, his Me c h an i c k s ; tranflatcd from his Fren cnl

manuscript; aNewPEicE.
ARCHIMEDES, his TraftDE In sii>entibus Humido; With the Note s and

Demonstrasions of NICOLAUS TARTALhUS. in Two Books.
G ALILEUS bis D 1 s c OUR s E of the things that move in or upon the W a t e r. i
NICOLAUS TARTALEUS his Inventions for Diving under Wat '

Raising of Ships sunk,&c. in Two Books.

T E R)

III.

PART THE SECOND. i

EVANGELTSTA TORRlCELLTUS,hisDocTRiNE of Proie cTS,andTAB le«^
of the Ranges ot great Gunns of allforts; wherein he deters fundr^
Errors in Gunmery s An Epitome.
T.S. his Experiments of the comparative Gravity of Bodiis in the

Aire and Water. , . _. „
CALILEUS G ALILEUS, his Life : mFivc Books,
Book L Containing Five Chapters.
ch4f. I. His Country.

3. His Par/»nci anj ExrraiO-inn.
3 His time ot Birth.
: His fitft Education.
^\ His Maftcrs.

II. Containing T hree Chapters.
/>/»p. I- His j'ldgracnt in fcvcral Learnings.

2. Hi> Opinions and Doftrine.

3. His Auditors and Scholars.

III. Containing Four Chapters.
Chap. 1. His behaviour in Civil Affairs.

2. His manner ot Living.

3. His morall Virtues.

4. His misfortunes and troubles.
iV. Containing Four Chapters.

rhav I. HiipcrCondefcribcd.

^ ^' 2. His Will and Death.

3. His Inventions.

4i His Writings.

5. HisDiabgues of the Syfteme in parti.cLiIar,cohtarningA7i«
Sia,o. I . O Aftronomy in General ; its Definition,Praifr6rS

3. Of the Doarine of the Earths Mobility.^J-c. ,-(5 Antimi.-tV

andPtogrcffe from P;,i.^,««othc\in,cof3

4. p theFollowcrsof<:»,,r.,w,u„tothctimeof£?ir«

5. O the fcvcrall Syftemcs amongft Afttonomer'.

6. Of the Allegations againfl the Syftcme in 77
Of A'^Ar"!- "''f T °* '^'th Anfwcrs totheffl^^

" OftheAlkgattonsfor thcC.,,r,.Syftemein ToArgumenK

9. The Conclufion Of the Whole Chapter.
V. Containing Four Chapters.

I- His Patrons, Friends, and Emulators,
a. Authors judgments of him.
5. Authors that have writ for, or againft him.
4. A Conclufion in certain Reflexions upon his whole Life,

A Table 0/ the wM Second Tome, j/j^

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

s and DEMON*
CO the Me c H A*

IcCentre oi

this Frbn €9,1

the Notes and
wo Books.

ic W A T E R.

NPER Water,

TS,andTAB le«

lODll s

in the

^PraiTe, Original.
" iloguc of the

^ Its Antiguicy»

:imc of Copernicus'

timcofGtiii/gw.
nomers.

'.Syftcmc, in 77
AnfwcrstotheitJ'
in 50 Argument'
gainftand for the

II Life.

G A L I L U

GalilsBus LyncsBUS,

SYSTEME

OF THE

The Firft Dialogue.

INTEKLOCVrOKS.
jSALviAtus, Sagredus, aiid Simplicius.

SALVIATUS.

T was our ycfierdayes refolution, and a,
grcemcnt,that we {hould to day d.fcourfe
the moftdiftinaiy, and particularly wc
could poffible, of the natural reatons,and
their efficacy that have been hitherto al-
ledged on the one Or other part , by the
maintainers of the Pontions^ ^r«ff.f«/,.«,
and PtolomanHch and by the tollowcrs CopernlcHs^w-;

■ of thfe eofcrmcan Syftcm : And bec^ufe

Copernicus placing the Earth among the moveable Bodie of tjea-
vel comes to conftitute a Globe for the lame hke to a Plan« , .t
would be good that we began our dilputation with the e^amuia-
tionofwhat, andhow great the ^^^'p f'^^ ^^'^f'!".'^'^^^^
guments is, when they demonftrate, that th,s Hypotbefis n ,.npo -

z G. Galilee us. bis Syfieme.

Coeiefliai fubf^an- ^^^^^ ' Slncc that it IS neccffary to introduce in Nature,fubftanccs
ces that arc fy>itite- different bctwixt theml'elvcs, that is^the Caleftial, and Elementa-
^f^wf/'X ^ ^^^^ impaflible and immortal , this alterable and corruptible.
rablr.arifiecejfary Which argument Arijiutle handlctji in his book Cc^lo-i infinu-
'hx\Li\t'''°'' "-^atingit fiift, by fome difcourfes dependent on certain general af-
fumptions^and afterwards confirming it with experiments and per-
ticulardemonftrations : following the fame method, I will pro-
pound 5 and freely fpeak my Judgement , fubmitting my felf to
your ceniure, and particularly to Stmplic ins ^ 2i^to\xt Champion
and contender for the Arifiatelian Do&rine. ^
Ariftotle maketh And the firft Step of the Fcripatetick arguments is that5whcre A-
the mridferfeit, riftotU provcth the integrity and perfcftion of the World, telling

Brecaufe tt hath the , ^ . i i- ' r r r - » » i

threefold demenft- US , that It IS not a limpk luie, nor a bare lupcrhcies , but a body
adorned with Longitude, Latitude, and Profundity , and becaufc
there are no more dimenfioiis but thefe three , The World having
them, hath ^^ill, and having all, is to be concluded perfe/&. And
agaiivhatby fimple length, that magnitude is conftitilted, which
is called a Line 5 to which adding breadth? there is framed the Su-
perficies, and yet further adding the altitude or ptofounditys there
refuUs the Body, and after thefe three dimenfions there is no
pafling fafther,lo that in^-tbef^thr^ the iotcgfity, an4 to4i>.ipeak,
tptaJiry is terminated; which I might but with juftic^ have requi-
red Arijiotle to have proved to me by neceflary coniequcnces, the
rather in regard he was able to do it very plainly, andfpccdily.
Simp l. What fay you to the excellent demonflracions i-. the

Ariftotlcs^^w^"*- 3. 3-and4. Texts, after the definition of ContimtaP, have you it

^hedZ^fio^toL ^^^'^ P^""^^"^ ' ^^^^ ^^^'^ no more but three dimenfions,

^ three and no more, fot that thofc thrcc are all things, and that they are every where?
7hemmher three ^^^^ ^^ not this Confirmed by the Doftrine and Authority of the
ceiUZTedLo-^gfi Fythagorians^ who fay that all things are determined by three, be-
t^^Pythagorians ginning, middle, and end, which is the number of All ? And where
leaye you that reafon, namely, thut at it were by the law of Na-
ture, this number is ufed in the r4crilices of the Gods ? And why
being fodiftated by nature, do \ve atiibute to thofc jihings th^^t
are three, and nor to leUe, the title of all ? why of tWo jsit faid
both,and not all, unlefs they be three ? And all thisDoflrrine yoii
have in the lecond Text. Afterwardb in the third , Ad pleniorem
Omnejotum Sc fcientiam^ we read that All^ the Whole , and Ferfecl^ are formally
Pcrtc£tum. and the fame ^ and that therefore oaely the Body^ SLxnovigfh

magnitudes is perfcft : becaufe it is determined by three, which is
All, and being divifible three manner of waies, it is every way di-
vifible 5 but of the others, fome are dividible in one manner, and
fome in two, becaufe according to the number affixed, they have
' their divifion and continuity, and thus one magnitude is continu-
Or Solid. ate one way, another two, a third, namely the Body , every way.

More-

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

cs
nta-
ruptible.
kinfitiu-
Pralaf.
and pcr-
will pro-
ly ielf to
bampion

I, telling
t a body
[ becaufe
Phaving
I And
d, which
|the Su-
there
K is no
iTpeak,
ve requi-

I^s, the
1^: the
you it
Uions,
f where?
ty of the
hree, be-
id where
Epf Na-
n why
B tba;t
If f faid
trine you
morcm

Dialogue. L

Moreover in the fourth Text i doth he not after fome other Do-
flirineS) prove it by another denionftration ? SciUcetyThsit no tran-
fitionis made but according to fome defcS: (and fo there is a tran-
fition or paffing from the line to the fupcrficies, becaufe the line is
defeSive in breadth^ and that it is impoflible for the perfeft to
want any thing, it being every way foi therefore there is no tran-
fitionfrom the Solid or Body to any other magnitude. Now
think you not that by all thefe places he hath fufficiently proved,
how that there's no going beyond the three dimenfions , Length,
Breadth , and Thicknefs , and that therefore the body or folid,
which hath them all, is perfeft >

Salv. To tell you true, I think not my felf bound by all thefe
rcafons to grant any more but onely this, That that which hath
bcginning,middle,and cnd,may5and ought to be called perfeftiBut
tliat then, becaufe beginning, middlcjand end,are Threc,the num-
ber Three is a perfeft number , and hath a faculty of conferring
FerfeSion on thofe things that have the fame, 1 find no inducement
to grant h neither do I underftan4> nor belieye that, for example,
of feet, the number th-^- t^ more perted then Tour ur rwo^ por do
Iconceiyc nunibcr four to be ^ny imperfefiion to the Elc-»
mcnts : and that they would be more perfefl: if they ^y^;e three.
Better therefore it had been to have left thefe fubtlettes tp the
^etoricians^dind to have proved hisintent,by neccffary demonftra-
tion j for fo it behoves to do in demonftrativc fcicnces.

S I M p L. You feem to fcorp thefe rcafons, and yet it is all the
Doftrine of the Pythagorians^ who attribute fo much to numbers .
and you that be a Mathematician^ and believe many opinions in
the Py th^gprich^ Pl^lpfophy , feem now to contemn their My-
fteries. J

Salv. That the Pythagorians had thcfcience ofpunibersin
high eftecm, and that Plato himfelf admired humane underftand-
i^Jg, and thought that it pertook of Divinity , for that it under-
ftood the nature of numbers, I know very well, nor fliould I be
far from being of the fame opinion ; But that the Myfteries foi?
^hich Pythagoras and his feft, had the Science of numbersin fuch
veneration, are the follies that abound in the mouths and writings
of the vulgar,! no waies credit:butrather becaufe I knovv that theyj
to the end admirable things ijiight not be e^pQf<?d tp (he cout
tempt, and fcorne of the vulgar, cenfured as facriiegiouSj f he pub?
lifliing of the abftruce properties of Number^ , and i/icommen-
furable and irrational quantities , by them inveftigated j and di-
vulged,that he who difcovered them, was tormented in the other
World : 1 believe that fome one of them to deter the common
fort, and free himfelf from their inquifitivenefs, told them that the
niyfteries ofnumbers were thofe trifles, which afterwards did fo

A 2 fpread

Plato held tfjit
humane uader-^
fianding partook
ofdivtnitjj^ecaHje
it Understood num*
hersi

The^yjlcry of
Pythagorjck««iw-
hers fabulous.

De Papyriop i-
texcato , Gelliui i ->

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

4 G. G A L 1 L ^ u s, bis Sjllemel

fpread amongft the vulgar, and this with a difcretion and fubtlety
refembling that of the prudent y6ung man, that to be freed
from the importunity of his inquiiitive Mother or Wife, I know
not whether, who preffcd him to impart the fecrets of the Senate,
contrived that ftory , which afterwards brought her and many o«
thcr women to be derided and laught at by the fame Senate.

S I M P L. I will not be of the number of thofe who arc over curi-
ous about theP)/t/^^^(>ricl^ myfteries 5 but adhering to the point
in hand j 1 reply, that the rcafons produced by Ariflotle to prove
the dimenfions to be no more than three , feem to me conclu-^
dent, and 1 believe,That had there been any more evident demon-
ftrations thereof, Arijtotle would not have omitted them.

S A G R. Put in at leaft,if he had known,or remembred any more.
But you Sal^iatHs would do me a great pleafure to allcdge unto
me fome arguments that may bcevident,and clear enough for mc
to comprehend.

S A 1 V. I wilh and they (hall be fuch as are not oncly to be ap-
prehended by you , but even by Simplicius himfclf : nor oncly
to be comprehendca , but arc alfo already known , although hap-
ly unobferved j and for the more eafie underftanding thereof,
wc will take this Pen and Ink , which I fee already prepared for
ACeomeHcMlde- fuch occafions, and defcribc a few figures. And firft we will note
TfuJ^mnf^^^ [Fig.i • of this Dialog,'] thcfe two points AB, and draw

tr»p t mcnfton. ^^^^ ^j^^ ^^j^^^ ^j^^ curved lines,ACB,and ADB,and the

right line A B, I demand of you which of them, in your mind, is
that which determines the diftance be tween the terms AB, & why?

5 A G R. 1 fliould fay the right line, and not the crooked, as well
becaufe the right is fliorter , as becaufe it is one, fole , and deter-
minate, whereas the others arc infinit,uneqnal,and longer^ and my
determination is grounded upon that,That it is one,and certain.

S A LV. We have then the right line to determine the length be-
tween the two termsi let us add another right line and parallel to
AB,which let be CD,[f fo that there is put between them a
fuperficies,of which I defire you to affign me the breadth,therefore
departing from the point A, tell me how, and which way you will
gOjto end in the line C D,and fo to point me out the breadth com-
prehended between thofe lines j let me know whether you will
terminate it according to the quantity of the curved line A E, or
the right line A F, or any other.

S I M P L* According to the right A F , and not according to the
crooked, that being already excluded from fuch an ufe.

S AG R. But I would take neither of them, feeing the right line
A F runs obliquely ^ But would draw a line , perpendicular to C
D, for this fliould feem to me the fliorteft, and the propereft of
infinite that are greater^and unequal to one another,which may be

pro-

ALOGUE

)tlety
^- freed

i know
Icnate,

iny Om

fr curi-
point
prove
iconclu-^
■eiiion-

Hmore.

Ige unto
for mc

3e ap-
^onely

; thereof,
>ared for
will note
Lnd draw
^,and the
mind, is
tSc why?
ns well
H deter-
l^and my
P^ain.
^th bc-
irallel to
:i them a
i|trefore
P^u will
Kh corn-
will
or

^to the

Sht line
lar to C
pereft of
I may be
pro-

produced from the term A to any other part of the oppofite line
CD.

Sa.lv. Your choice, and the reafon you bring for it in my judg-
ment is moft excellent fo that by this time we have proved that
the firft dimenfion is determined by a right line, the fecond name-
ly the breadth with another line right alio , and not onely right,
but withall, at right-angles to the other that dctermineth the
length , and thus we have the two dimenfions of length and
breadth, definite and certain. But were you to bound or termi-
nate a height, as for example, how high this Roof is from the pave-
ment, that we tread on, being that from any point in the Roof,
we may draw infinite lines, both curved, and right, and all of di-
yerfe lengths to infinite points of the pavement, which of all thefe
lines would you make ufe of ?

S A G R. I would fallen a line to the Seeling,and with a plummet
that fliouldhang at it, would let it freely diftend itfelftillit
fliould reach well near to the pavenlent , and the length of fuch a
thread being the ftreighteft and fliortefl of all the lines, that could
pofsibly be drawn ^-^'•^ ^"^ ^^^^^ P^"^^ ^^^^ pavement, I would
iay was the true height of this Room.

S A L V. Very well, And when from the point noted in the pave-
ment by this pendent thread ( taking the pavement to be levcll
and not declining) you fliould produce two other right lines j one
for the length, and the other for the breadth of the fuperficies of
thcfaid pavement , what angles fliould they make with the faid
thread >

Sagr. They would doubtlefs meet at right angles, the faid
lines falling perpendicular,and the pavement being very plain and
levcll.

Salv. Therefore if you aflignany point, for the term from whence
to begin your meafure , and from thence do draw a right line, as
the terminator of the firft meafure , namely of the length, it will
follow of neceffity, that that which is to defign out the largenefs
or brcadth,toucheth the firft at right-angles,and that that which is
to denote the altitude, which is the third dimenfion, goiog from the
fame point formethalfo with the other two, not oblique but right
angles, and thus by the three perpendiculars, as by three lines,one,
certain, and asfhort as is poffible, you have the three dimenfions
A B length-; A C breadth, and A D height i and becaufe, clear it
that there cannot coneurre any more hneein thcfaid point, fo
to make therewith ri^ht-angles , and the dimenfions ought to
be determined by the fole right lines, which make between them-
felves right-angles j therefore the dimenfions are no more, but
three, and that which hath three hath all, and that which hath all,
is divifible on all fides, and that which is fo, is perfefi:, &c, .

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

5 G. G A LiL^ us. his Syfteme.

Sim PL. And who faith that I cannot draw other lines ? why
may not 1 protraft another line underneath, unto the point A,
that may be perpendicular to the reft ?

Salv. You can doubtlefs, at. one and the fame point, make no
more than three right lines concurre, that conftitutc right angles
between themfelves.

Sagr. liccyvh^tSimpliciHSxacMs^ namely, thatfliould the
faid D A be prolonged downward^then by that means there might
be drawn two others, but they would be the fame with the firfi
three, differing onely in this, th^it whereas now they onely touch,
then they would intcrfwfi , but not produce new dimenfions.
/« phjific4i proofs s I M P L. I will not fay that this your argument may not be con-
cludent *, tut yet this I fay with ArijlotU^ that in things natural
n- it is not alwaies necelTary, to bring Mathematical deinonft rations.

Sagr. Grant that it were fo where fuch proofs cannot be had
yet if this cafe admit of them, why do not you ufe thein ? Bu^ it
would be good we fpent no ifiore words on this particular, for I
think that Sahiatus will yield , both to Ariflotle^ and you, with-
out farther dcmQnftr^>^on>that the Wpild is a body, and perfeft,
yea moft perfeftj as being the greateft work of Qod.

Salv. So really it is, chercfotre lcs^yi«g the geuerai coatempla-
"Fartsol thiworU tion of thc wtolc, let US defccnd to the confidcration of its parts
V^ZZTcZ which Ariftoth^ti his firft divifion,makes two, and they very diffe'
fti4i Mnd Elemen- rent and ahiioft contrary to one anotfeec i namely the Cocleftial
" Elementary : that ingencrable, incorniptible,^nalterabIe,un.'
paffible, &c and this expofed to a continual alteration, mutati-
on,&c. Which difterence, as from its original principle , he de-
rives from the diverfity of local motions , andia ^hjs method he
proceeds.

^Leaving the fcnfible, if I m^y (o fpeak, and retiring into the
Ideal World, he begins Architeftonically to conlider^hat nature
W motion of feeing thc principle of motion,, itfoUowcth that oat^ral.bodics be
three kinds, right, indued with local motion. Next he dec 10^4] niotion tP i)«
€ircHiar,&mixt. of three kinds, namely, circular, right, and mixt of «iglit and eif-
CircuUr , and cuUr : and the two firft he calleth fimpte, for th^t ^ ^\\ hnes the
^""ifm ieZT7o- ^^^^^^^^ ^ and right arc onely fimple s and here fQmewhat rc-
7eedinlh /?m7/<r ft raining hi mfclf, hedcfinethanew, of fimple morions, one to be
linei. circular, namely that which is made about the medium , and the

other namely the right, upwards, and downwards s.Oipvyards, „tUat
wliich movcth from the downwards, that wjbjch goeth to-

wards the medium. . ^iid from hence heinfcrsjashe may byandne-
f J ceffary confequence , that all fimple mot^)ns are <:(infined to thefe
tbree kinds, namely,to the medium, from the medintu^ and about
the medium 5 thc which correfponds faith he, with what hath been
faid before of a body, that it alfo is perfefted by three things,aiid fo

_ Dialogue. I. ^

is its motion. Having confirmed thefe motions,he proceeds faying;
that of natural bodies fome being fimple , and fome compofed of
them ( and he calleth fimple bodies thofe , that have a principle
of motion from nature, as the Fire and Earth ) it follows that
fimple motions belong to fimple bodies, and mixt to the com:
pound; yet mfuch fort, that the compounded incline to the part
predominant i n the compofition.

SAGR. Pray you hold a little Sal'z^iatm , for I find fo many
doubts to fpring up on all fides in this difcourfe , that 1 {hall be
conftrained , either to communicate them if I would attentively
hearken to what you fliall add, or to take ofFmy attention froiri
the things fpoken, if I would remember ob jeaions>

S A i. V. I will very willingly ftay , for that I alfo run the fame
Hazard, and am ready at every flep to lofe my felf whilfi: I fail be-
tween Rocks,and boifterous Waves, that make me, as they fay, to

V ' therefore before I make them more , propound

your difficulties. ^

Sagr. You and yfr/f -a-*'— ; w^ai firft takemea

uttleoutof theC?»«""e World, to tell me of the ^r<rWa«r# f ^T''"'*"'
Wherewith it ought to be fabricated , and very appofitly begin to
tell me, that a natural body is by nature moveable , nattire being
( 5is ellewhcre it is defined ) the principle of motion. But here I
~ am lomewhat doubtfull why ArijkotU faid not that of natural bo-
dies, (ome are moveable by nature , and others immoveable, for
that in the definition, nature is faid to be the principle of Motion,
and Reft i for if natural bodies have all a principle of motion,
cither he might have omitted the mention of Reft, in the definiti-
oa ot nature :or not have introduced fuch a definition in this pl^.e.
Mext, as to the declaration of what J rijiotle intends by fimple
motions, and how by Spaces he determines them^calling thofe fim-
ple, that arc made by fimple lines , which are onely the right, and
circular, I entertain it willingly^ nor do I dcfire to tenter the ^-^'-^ "^^^^
inftance of the Helix,about the Cylinder which in that it is in e- tja^':^^:^
very part like to it felf, might feemingly be numb red amoiig fini^ puihc,
pie lines. But herein I cannot concurre, that he fliouldfore^ •
ftrain fimple motions (whilft he feems to go about to repeat the
fame definition in other words) as to call one of them the ^notion
about the;;;/c&w»/, the others 5'«r/>/;;/ ^ Deorfnnt, namely up-
wards and downward i which terms are not to ^c ufed, out of the
World fabricated, but imply it not onely made , but already in-
habited by us ^ for if the right motion be fimple, by the fim|>iicity
of the right line, and if the fimple motion be natural, it is made on
every fide, to wit, upwards, downwards, backwards, forvvards, to'
the right, to the left , and if any other way can be imagined, pro^
Videditbeftraight, it fliall agree to any fimple natural bc^dy^^ or

Ariftotle accom-
moeUtes the rules ej

Archirc£):nre to
the frtrnt tf the
fVorld^ a'-dnotthe
frame to thtrnltt.

Jtight met im, fame-
times pmpl/'y ar.d
fomtttmes mixt mc-
C9rd$n^t9 Arift*

G. G A L 1 L /E u bis Syfieme.

if not fo, then the fuppofion of Arifiotle is defefiive. It appears
moreover that yiri/?<7^/chinteth but one circular motion alone to
be in the World, and confequently but one oncly Center, to
which alone the motions of upwards and downwards, refer. All
which arc apparent proofs, that -^ri/iot/^/ aim is, to make white
black, and to accommodate ArohiteSiHr^ to the building, and not
to modle the buildirig according to the precepts of Artbite^ure :
for if I fliould fay that Nature in Univerfal may have a thou-
fand Circular Motions , and by confequence a thoufand Cen-
ters , there would be alfo a thoufand motions upwards , and
downwards. Again he makes as hath been faid, a fimple motion
and a mIxt motion, calling fimple , the circular and right \ and
mixt, the compound of them two : of natural bodies he calls fome
fimple ( namely thofe that have a natural principle to fimple mo-
tion) and others compound : and fimple motions he attributes
to fimple bodies, and the compounded to the compound but by
compound motion he doth no longer underftand the mixt of right
and circular, which may be in the World j but introduceth a mixt
motion as impoiBblc, as it is impofliblc to mixe oppofite motions
insiac in the fame right line, fo as to produce from them a motion
partly upwards, partly downwards ^ and, to moderate fuch an ab-
iurdity , and impoflTibility, he aflbrts that fuch mixt bodies move
according to the fimple part predominant : which neccflitates
others to fay, that even the motion made by the fame right line is
fomecimes fimple, and fometimes alfo compound : fo that the fim-
plicity of the motion , is no longer dependent onely on the fim-
plicityof the line.

S I M P L. How? Is it not difference fufficient,that the fimple and
abfolutc arc more fwift than that which proceeds from predomi-
nion ? and how much fafl:er doth a piece of pure Earth defccnd
than a piece of Wood ?

S A G R. Well, Simplicius j But put cafe the fimplicity for this
caufe was changed, befides that there would be a hundred thou-
fand mixt motions, you would not be able to determine the fim-
ple j nay farther, if the greater or lefle velocity be able to alter
the fimplicity of the motion, no fimple body (hould move with a
fimple motion j fince that in all natural right motions, the veloci-
ty is ever encreafing, and by confequence fl:ill changing the fimpli-
city , which as it is fimplicity, ought of confequence to be immu-
table, and that which more importeth, you charge Arifiotle with
another thing , that in the definition of motions compounded, he
hath not made mention of tardity nor velocity , which you now
infert for a necefTary and eflfential point. Again you can draw
no advantage from this rule , for that there will be amongft the
mixt bodies fome, (and that not a few^ that will move fwiftly^

and

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

D I A L O G U E L " ^
and others more flowly than the fimple^ as for example, Lead, and
Wood, in comparifon of earth j and therefore amongft thefe ffio-
tions, which call you the llmple, and which the mixi.?

Sim PL. I would call that fimple motion , which is made by a
fimplc body , and mixt, that of a compound body.

S A G R . Very well, and yet Simplicius 2l little before you faid,
that the fimple, and compound motions , difcovered which were
mixt, and which were fimple bodies ^ now you will have me by
fimple and mixt bodies, come to know which is the fimplc , and
which IS the compound motion : an excellent way to keep us igno-
rant,both of motions and bodies. Moreover^ you have alfo a little
above declared, how that a greater velocity' did not fuffice , but
you feck a third condition for the definement of fimple motion, for
which Arijiotle contented himfelf with one alone, namely, of the
limphcity of the Space, ov Medinm : But now according to youi
the fample motion, (hall be that which is made upon a fimplc line,
with a ccrrain determinate velocity , by a body fimply moveable.
JNow be It as you plcafe, and 1^. ro ^r^JiotU , who defi-

neth the mixt moti»^" °^ that compounded of the right and cit
cular, but proauceth Hot any body, which naturally moveth with
fuch a motion.

A/i^t^ J" ' •gain to , who having very well, and

Methodically begun his difcourfe ; but having a greater aim to
k- L*^;. P^'cdcfigned in his minde, then that to

whish his method lead hiin, digreOing from the purpofe, he comes
to aUert, as a thing known and manifcft , that as to the motions
dircetly upwards or downwards, they naturally agree to Fire, and
Harth and that therefore it is neceffajy, that befides thefe bodies,
which are necr unto us, there muft be in nature another, to which
the circular motion may agree : which (hall be fo much the more
excellent by how much the circular motion is more perfea,then the
ftreight, but how much more perfeft that is than this , he deter-
mines from the greatnefs of the circular lines pcrfefiion above the , /•
right line calling that perfeft, and this imperfeft j imperfeft, be- perfeH: , according
caule it infinite it wanteth a termination, and end : and if it be fi- ^'f ""^'7 '"''^
-nite, there is yetfomething beyond which it may be prolonged. f^V^^^^^w^^
1 nis is the bafis,ground work, and mafter-ftone of all the Fabrick
oi^QArmotdian World, upon which they fup^rftrua all their
Pther properties, of neither heavy nor light, of ingenerable incor-
^ptible, exemption from all motions , fome onely the local, Sec.
^^dall thefe pafiions he affirmetli to be proper to a fimple body
that IS moved circularly j and the contrary qualities of gravitv,
levity, corruptibility,8a:. heafli gns to bodies naturally moveable
in a ftreight line , for that if we have already difcovered defeats in
the foundation^ we may rationally queftion what foevcr may far-

B ' thcr

G. Galil^us, Us Syfleme.

thcr built thereon. I deny not, that this which Ariftotle hitherto
hath introduced, with a general difcourfe dependent upon univer-
ial primary principles,hathbeen fince inproccfs of time, re-inforced
with particular reafons, and experiments j all which it would be
neceffary diftinftly toconfider and weigh , butbecaufe what hath
been faid hitherto prefcnts to fuch as confider the fame many and
no fmall diflSculties , ("and yet it would be neceffary, that the pri-
mary principles and fundamentals, were Gcrtain,firm, and eftablilh-
ed, that fo they might with more confidence be built upon J) it
would not be amifs, before we farther multiply doubts, to fee if
liaply (as I conjedure) betaking our fclves toother waies, we may
not light upon a more direft and fecure methods and with better
confidercd principles of Architefturc lay oui* primary fundamen-
tals. Therefore fufpending for the prefent the method of Artjio-
tlcy C which we will rc-affume again in its proper place, and parti-
cularly examine « ) I fay, that in the things hitherto affirmed by
'''ofed blithe aI' him, I agree with him, and admit that the World is a body enjoy-
%ortoL \!rfemj ing all dimenfions, and therefore moft perfeS \ and I add, that as
ordin<*t€. ^^^j^ 0eceffartly moft Ordinate, that is, having parts between

themfclves, with exquifite and moft perfeft order dil'pofcd j which
affumption I think is not to be denied, neither by you or any

^^'s i*M P L- ^^^y ^ particular (of the worlds

diiTienfions) is taken from Ariftotle himfclfj and its denominati-
on of ordinate fcems onely to be affumed from the order which it
moft exaftly keeps.

Streight motion SaLV. This principle then cftabliflied, one may immediately
*^!^ulxAVklj 'or- conclude, that if the entire parts of the World Ihould be by their
difiMte. nature moveable , it is impoffible that their motions fliould be

right, or other than circular *, and the reafon is fufficiently eafie,
and manifeft h for that whatfoever moveth with a right motion,
changeth place ^ and continuing to move, doth by degrees more
and more remove from the term from whence it departed, and
from all the places thorow which it fucceffivcly paffcd ^ and if
fueh motion naturally fuited with it, then it was not at the be-
ginning in its proper place j and fo the parts of the World were
not difpofed with perfeft order. But we fuppofe them to be per-
feaiy ordinate, therefore as fuch, it is impoffible that they ftiould
by nature change place, and confequently move In a right moti-
jtiibt motion hy on. Again, the right motion being by nature infinite, for that
nitture infinite, the tight line is infinite and indeterminate, it is impoffible that
Motion hy a right any movcable cau have a natural principle of moving in a right
popicT'*^^^ line^ namely toward the place whither it is impoffible to arrive,
Natnre attempts thcrc being uo prac-finitc term '■, and nature, as Arjjiotle himfelf
iVtlTeKffTilt' faith well, never attempts to do that which can never be done.

nor

Ibc .

s «

pri-
liOi-

^ «
eeif

may

:tter
nen-

Joy-

mch

any

is
ti-
I'at

ly
heir
1 be

iif

3tl-

(hat

Tive,
mfdf

ftor

■L

D I A L b G li te I. ' n

nor effaies to move whither it is impoflible to arrive. And if any
onefhoLild yctobjeft, that albeit the right line, and confcqucnt-
ly the motion by it is producible in injiHitmn^ that is to fay, is in-
terminate^ yet neverthclefs Nature, as one may fay, arbitrarily
hath affigned them fome terms, and given natural inftinfts to
its natural bodies to move unto the fame \ 1 will reply, that this
might perhaps be fabled to have come to pafs in the firft Chaos, R^ghtn^ouonmigl^
where mdiftinft matters confufedly and mordmately wandered h firfi chaos.
to regulate which. Nature very appofitely made ufeof right mo- f^^^^J^J'^'^^
tions, by which, like as the well-conftituted, moving, difdorder ^^^^^^^ /'^r^/^^^
themlelves, fowere they which were before depravedly difpoicd om of or-
by this motion ranged in order :*but after their exquifite diftribu-
tion and collocation, it is impolTible that there fliould remain na-
tural incHnations in therri of longer moving in a light motion,
from which now would cnfue their removal from their proper and
natural place, that is to fay, their difordinaiion ^ we may there-
fore fay that the right motion fervcs to conduft the matter to ereft
the work j but once crefted, that it is to reft immoveable, or if
moveable, to mov. — -"^'Y J'-^CuUrij. «„ur. we will (^yZT/^.u'lt
with Flato, tncic mundane bodies, atter they had been made ^/««/>;^ /« artgh't
and finiflied, were for a certain time moved by their Maker, in a ^'^'^^^^ ''''frcHUri'
right motion, but that after their attainment to certain and dc- 7ccordhitov7i^^^^
terminate places, they were revolved one by one in Spheres, paf-
fing from the right to the circular motion, whefeiu they have
been ever fince kept and maintained. A fublime conceipt , and
worthy indeed of Plato : upon which, I remember to ha;ve heard * Thus dorMis co^
our common friend the "^Lyncean A cade mic k^diicomk in this man-
net, if I have not forgot it. Every body for any reafon conftitu- throughout this
ted in a ftate of reft , but which is by nature moveable, being fet
at liberty doth move ^ provided withal, that it have an inclina- i„g ,« a ftate of
tion to fome particular place h for flibuld it ftand indifferently af- r e ft ^ (hail move

r r> 1 ,1 . t 1 ... n 1 • • f*»lefs it have an

icaed to all, it would remain m its reft, not having greater m- iMn^tton to fame
ducement to move oneway than another. From the having o£ panicuUr pUcc.
this inclination necelTarily proceeds, that it in its moving ftiall con- ^.^^^ ^,^,ahie ac-
tinually incrcafe its acceleration, and beginning with a moft flow ceUrates its moti-^
motion, it fliall not acquire any degtee of velocity, before it 2) ,XI^r
fliall have paffed thorow all the degrees of Icfs velocity, orgrea- ^v/j^,/,
ter tardity : for pafling from the ftate of quiet (which is the in- ^'7. . . ■
hnite degree of tardity of motion) there is no reaion by which f,„^fromrejr,
Y fliould enter into fuch a determinate degree of velocity, before cth '^^^^^^^fj^'
|t fliall have entred into a lefs, and into yet a lefs, before it cntred
into that : but rather it ftands with reafon, to pafs firft by thole
degrees neareft to that from which it departed, and from thofe to
the more remote ^ but the degree from whence the moveable Reft the i»ft»ite
began to move, is that of extreme tardity, namely of teft. 'i''^<', t'^rdtty,

B 2 Nov^>

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

Nature^ to ixtro-
dnce tn the move-

12 G. G A L 1 L ^ u bis SjjJeme.

The moveahle doth Now this acceleration of motion is never made, but when the
7»iy^^tZpp^^^^ moveable in moving acquireth it ^ nor is its acquift other than an
eth nearer to its approaching to the place defired, to wit, whither its natural in-
clination attrafts it, and thither it tendeth by the Ihorteft way \
namely, by a right line. We may upon good grounds therefore
fay. That Nature, to confer upon a moveable tirft canftituted in
reft a determinate velocity, ulcth to make it move according to
a certain time and fpace with a right motion. This prefuppofed,
able a certat» de- let US imagine God to have created the Orb %;,g, of Jupiter^ on
gree of velocity, ^j^j^h he had determined to confer fuch a certain velocicv, which

made It move tn a j r • ii -r

ri^htiine, it ought aftctwards to retain perpetually uniiorm ? we may with
Plato {^y^ that he gave it at the beginning a right and accelerate
motion, and that it afterwards being arrived to that intended dc-
Vmform velocity giee of Velocity, he converted its right, into a circular motion
Z'^rZZ^L^ion!' the velocity of which came afterwards naturally to be uniform.

S AGR. 1 hearken to this Difcourfe with great delight 3 and I
believe the content I take therein will be greater, when you have
fatisfied me in a doubt : that is, Cwhich I do not very welicom-
prehendj how it of neceffity enfucs, that a moveable departing
al^'^Jp '^'A fj-oin j.^, and cutting into a motion to which it had a natural
T-i^cfj^ty^^^^^^ inclination, it paffeth thorow all the precedent degrees of tardity,
*i.^r«/ z/.- comprehended between any aflfigned degree of velocity^ and the
locny interfofe. ^^^^ ^£ ^^^^ ^hich degtces ate infi nite ? fo that Nature was not
able tp confer them upon the body of Jupitery his circular moti-
on being inftantly created with fuch and fuch velocity.
Nature doth mt SALv. I neither did, nor dare fay, that it was impoflible for
'^rtttrJnZ God or Nature to confer that velocity which you fpeak of, imme^
degree of velocity^ diatcly j but this I fay, that dtfaBo fhe did not doit \ fo that the
hov^heiti^e could. ^^.^^ ^^^^jj ^ ^^^|^ extra-natutal, and by confequence mi-

raculous.

5 A G R. Then you believe, that a ftone leaving its reft, and en-
tring into its natural motion towards the centre of the Earth, paf-
feth thorow all the degrees of tardity inferiour to any degree of
velocity ?

Salv- I believe it, nay am certain of it \ and fo certain,
that I am able to make you alfo very well fatisfied with the truth
thereof.

Sagr- Though by all this daies difcourfe 1 Ihouldgainno
more but fucK a knowledge, I fliould think my time very well
beftowed.

Salv- By what I colk£t from our difcourfe, a great part of
your fcruplelieth in that it fliould in a time, and that very (hort,
pafs thorow thofe infinite degrees of tardity precedent to any ve-
locity, acquired by the moveable in that time : and therefore be-
fore wc go any farther, I will feek to remove this difficulty, which

fliall

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

Dialogue. I.

nan

core

bich
mh
rate

ion.

me-

Lin,

no
|11

»rt,
^e-
)e-
ich
all

ihall be an eafie task i for I reply, that the moveable paffi
the a forefaid degrees, but the paffage is made without fl:aj_..^_.
any of them j fo that the palTage requiring but one fole inftant
of time, and every fmall time containing infinite inftants, we fliall
not want enough of them to aflign its own to each of the infinite
degrees of tardity, although the time were never fo ftiort.

S AGR. Hitherto I apprehend you y neverthelefsit is very much
that that Ball (hot from a Cannon ( for fuch 1 conceive the ca-
dent moveable ) which yet we fee to fall with fuch a precipice,
that in lefs than ten pulfcs it will pafs two hundred yards of al-
titude 5 fliouldin its motion be found conjoyned with fo fmall a
degree of velocity, that, fhouldit have continued to have moved
at that rate without farther acceleration, it would not have paft
the fame in a day.

^S\LV- You may fay, nor yet in a year, nor in ten, no nor in a
thoufand 5 as 1 will endeavour to (hew you, and alfo happily with-
out your contradiaion, to fome fufliciently fimple queftions that
I will propound to you. Theref«r^^ell me if you make any que-
ftion of granting ti-*> ^^^^^ that ball in defcending gocth indca-
fiaQitsi^r'f^ and velocity.

S A G R. I am moft certain it doth.

S AL V. And if 1 fliould fay that the impetus acquired in any
place of its motion, is fo much, that it would fuffice to re-carry
it to that place from which it came, would you grant it ?

S A G R. I fliould confent to it without contradiftion,provided al-
waics, that it might imploy without impediment its whole impetus
in that fole work of re-condufting it felf, or another equal toit, to
that felf-famc height as it would do, in cafe the Earth were bored
thorow the centre, and the Bullet fell a thoufand yards from the
faid centre, for I verily believe it Would pafs beyond the centre^
afcending as much as it had defcended ^ and this I fee plainly in
the experiment of a plummet hanging at a line, which removed
from the perpendicular, which is its ftate of reft, and afterwards
let go, falleth towards the faid perpendicular, and goes as far be-
yond it 5 or onely fo much lefs, as the oppofition of the air, and
line, or other accidents have hindred it. The like I fee in the wa-
ter, which defcending thorow a pipe, re-mounts as much as it had
defcended.

S A L V. You argue very well. And for that I know you will not
fcruple to grant that the acquift of the impetus is by means of the
receding from the term whence the moveable departed, and its ap«
proach to the centre, whither its motion tendeth ^ will you flick
to yeeld, that two equal moveables, though defcending by divers
lines, without any impediment, acquire equal impetus^ provided
that the approaches to the centre be equal ?

SAGR;

The movfAhU de*
farting from rejl
pajfith thorow all
degrees of velocuj.
■wtthopit l^ajtttgi*''
Any,

The pottderom fkc^^
ver defcending ac
(ptireth jmpetu5
ftijficietit to rez
carry it to tkb Hk.!^
height.

G, Galilm usy bis Syfieme.

S A G R- 1 do not very well underftand the qucftion.
S A L V- 1 will exprelG it better by drawing a Figure : tlierefore
IwiUfuppofetheline AB [in Fi^-B-] parallel to the Horizon,
and upon the point B, I will ereft a perpendicular B C ; and after
that I adde this flaunt line C A. Undcrftanding now the hne C •
A to be an inclining plain exquifitely poliflied, and hard, upon
which defcendcth a ball perfedly round and of very hard matter,
and fuch another 1 fuppofe freely to dcfcendby the perpendicular
C B : will you now confcfs that the impetus of that which dc-
fcendsby the plain C A, being arrived to the point A, may be
equal to the impetm acquired by the other in the point B, after
thedcfcentbytheperpendicularCB? ,
r r <; » ^ B 1 lefolutely behevc fo : for in effeci they have both the
ItTrS fame pro;imity to the centre, and by that, which 1 have already
approachir^g to the their impetuofities wouM bc equally fufficicnt tore-carry

centre^ are eqt*al. gi'^Ait 5 ^ 1 •

them to the lame height.

S A L V- Tell me now what you believe the fame ball would do
put upon the Horizontal plane A B ?
L ■ Q /r^ p It would lie mil, the faid plane having no decimation.

taiipunthcmove' g al v- But on the inclmmg plane C A it would delcend, but
M UethpiL . ^ ,han by the pcrpendicukr C B ?

.SaGR 1 may confidently anfwcr m the affirmative, it feem-
. jj^e necefTary that the motion by the perpendicular C B
(hmild be more fwift, thailby the inclining plane C Ai yet ne-
verthelefs, if this be, how can the Cadent by the inclination ar-
rived to the point A, have as much impetus^ that is, the fame de-
gree of velocity, that the Cadent by the perpendicular {hall have
in the point B ? thefe twoPropofitions feem contradiftory.
rhtveiocitybjthe Salv- Then you would think it much morefalfc, fliould I
incUningpUr^e^ e^ r ^j^^^ ^j^c velocity of the Cadents by the perpendicular, and
VjXyZm^^^^^^^ are abfolutely equal-, and yet this is a Propotition

etiUu W ihemo- . ^ jg ^j^^ ^j^is that the Cadent moveth more fwittly by

uonyj theyerpe., ^ .j,^!,,^ ,han by the inclination. ^ ' ,

SAGR. Thefe Propotitions to my ears lound very harlh : and
1 believe to yours Simplicim ^

S I M p L I have the fame fenfe ot them.
S ' I conceit you jeft with me, pretending not to compre-
hend what you know better than my felf : therefore tell me S,m^
pliciHS , when you imagine a moveable more fwift than ano-
thcr, what conceit do you fancy m your mmd ?

S I M P L. I fancie one to pafs in the fame time a greater ipace
than the other, or to move equal fpaces but in lelTer time.

SALV. Very well: and for moveables equally fwitt, "^^^^^

your conceit of them ?

SiMPL- I fancie that they pafs equal fpaces in equal timcs^

Salv-

dicuUr fwift er
than hy the inch
nation.

lALOGUE. 1.

pace

Its

-V-

S A L V. And have you no other conceit thereof tf

Sim PL. This I think to be the proper definition <
tions.

S A GR. We will add moreover this other : and call that equal
velocity when the fpaces paffed have the fame proportion, as the ^r/'pS
times wherein thev arpnaA o.,^;*.:. ^ ^-1 J /V • • ...nV.„«..;.HJ'

K • L — r**"*-*^ ij*v»^ i-Ait idiiic proportion, as tn(

times wherein they are paft, and it is a more univerfal definition. froporti^'n^tctf

S A L V. 1 1 is fo : for it comprehcndeth the equal fpaces paft irf '^"^
equal times, and alfo the unequal paft in times unequal, but pro-
portionate to thofe fpaces. Take now the fame Figure,and apply-
ing the conceipt that you had of the more haftie motion, tell me
why you think the velocity of the Cadent by C B, is greater
thanthevelocityof thcDcfccndent by CA>
n n ^ r ^* ^ ^^^^^ ' becaufc in the fame time that the Cadent
tharl " the Defcendent (hall pafsin C A, a part lefs

^ ^y^c i^u"^ ' thus it is proved, that the moveable moves
more iwittly by the perpendicular, than by the inclination. Now
ontider, it in this fame Figure on*- mav any way evince the o-
ther conceipt, and "-^^^ the moveables were cauaily fwift
by both the o A and C B.

S I M p L. I fee no fuch thing ^ nay rather it fcems to contradift
what was faid before.

S A L V. And what fay you, Sagredm ? I would not teach you
what you knew before, and that of which but luft now you pro^
ducedme the definition.

Sa gR- The definition I gave you, was, that moveables may
be called equally fwift, when the fpaces paffed are proportional
to the times in which they paffed i therefore to apply the defini-
tion to the prcfent cafe, it will be requisite, that the time of dq-
fcent by C A, to the time of falling by C B, Oiould have the
fame proportion that the line C A hath to the line C B ^ but I
underftand not how that can be, for that the motion by G B is
fwifter than by C A.

Salv. Andyetyoumuftofneceffityknowit. Tell mc a little,
do not thcfe motions go continually accelerating >

Sagr. They do i but more in the perpendicular than in the
inclination.

Salv- But this acceleration in the perpendicular, is it yet not-
withftanding fuch in comparifon of that of the inclined, tliat
two equal parts being taken in any place of the faid perpendicu-
lar and inclining lines, the motion in the parts of the perpendicu-
lar is alwaics more fwift,than in the part of the inclination ?

Sagr. i fay not fo : but I could take a fpace in the inclinati-
on, in which the velocity (hall be far greater than in the like fpacc
taken in the perpendicular j and this (hall be, if the fpace in the

perpen^

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Images reproduced by courtesy of the Royal Library, Copenhagen
2°K.B. 9,163

G. Galilmus, bis Sjfleme.

perpendicular fliould be taken near to the end C, and in the in-
clination, far from it.

SALV. You fee then, that the Propofition which faith, that
the motion by the perpendicular is more fwift than by the incli
nation, holds not true univerfally, but onely of the motions
which begin from the extremity, namely from the point of reft :
without which reftridiion, the Propofition would be fo deficient
that its very direfi contrary might be true ; namely, that the mo-
tion in the inclining plane is Iwifter than in the perpendicular •
for It is certain, that in the faid inclination, we may take a fpace
paft by the moveable in lefs time, than the like fpace paft in the
perpendicular. Now becaufe the motion in the inclination is in
fome places more, in fomc lefs, than in the perpendicular ; there
fore infome places of the inclination, the time of motion of the
moveable,lhaIl havc a greater proportion to the time of the motion
ol the moveable, by lome places of the perpendicular, than the
fpace paired, to the fpace paffed : and in Other places, the p^^o-
portion of the time to the time, ftall be le'fs than that of the
Ipace to the fpace.. As for example : two moveables dcpartinc.
from their ^^icfcence, namely from the point C, one by the per-
pendicular C B, [in and the other by the indlrnation C A
m the time that, in the perpendicular , the moveable flia II K..,'
paft all C B the other (hall have paft C T lefier. And thcrefo ^
the time by C T, to the imie by C B (which is equal ) lhall hav^
a greater proportion than the line C T to P R I, • \u l
4-othe/./., hath a greater propo';tion^h!„\oThl t^^^^
And on the contrary, if in C A, prolonged as much as if rel:
fite, onefl^uldtake a part equal to C I, but paft in lZt r
time; the time m the inclmation fiiallhave zhl proportion to
the tiihe m the perpendicular, than the fpace to the fpace If
therefore m tl^e mclination and pcrpendicwIaH= We tiiiy fuppofe
iuchfpac^s and vcJocities, that the proportion bctVvten the faid
fpaces be greater and lefs than the proportion of the times ; we
may eafily grant, that there are alfo fpaces, by which the times
ot the motions retain the fame proportion as the fpaces

S agb. I am already freed from my gr^ateft doubt, and con-
ceive that to be not onely poflible, but necefl-ary , which I but
jnow thought a contradiaion : but neverthelefs I underftand not

ye t that this whereof we now are fpeaking, is one of thefe'
pofl.bieor neceffary cafes ; fo as that it Luld^e tru. tha the
timeofdefcentby cA, to the time of the fall by C B hath the
fame proportion that the line C A hath to C B [ wheLeit may
without contradiaion be aflkmed, that the velocity by the i'cli^
nation G A, and by the perpendicular C B, are equal.^

SaLV: Content your fclf for this time, that I have removea

your

Dialogue. I.

yourbcfeiulicy; but for the knowledge of this, expeft it at
fome othe.- cnxe, na.nely when you (hall fee the matters con e
S SXS t""^^^^^^ ^^'''^'--k.; at which

fce how it t K P.^'"' '^'"g*^'- Whereby you

motions cilared ^ r f ' u 'f™ ^ ^'""'^^ ''^^'""'"g 'l'^
and the orh^f ^^^'^^"^^ <^ ^ g^^^^er than C T,

d^awrfroi A ""^"^heinterfeaionof the perpendicula

compare the ^oT" 'l^"''^^" by C A. But when we

thatn,adetprtrt^--^'^-?^ire^^^^^^^^^^
not, that themp.=-^ "y G A. continuing to defcend beyond mv
arnvc to A in fuch a time as is in proportion to th. u '
as the line C A is to the line C Lretlf^g t^t.Tft
purpofe , which was to (hew, that the grave moveable leaving
pSnTt^r^f all^thede" Sy!

Slinfrhe V T"""' t-Sf ' ^^•^^'^y '''^^ « ^^q"-eth
ber hTw^ Figure wliich we ufed before, letus remcm-

5^ and th7cfdT:' ?" ^'>^'>f-ndentby theinclin^n C
«:quired eaud d P^P^^dicular C B, were found to have

proceed Tc, ^ A : now to

thrplte T """^ notfcruple to grant, that upon ano-

her plane left ftccp than AC ; as for example, A D [ia Fi^.< 1
the motion: of the defce«dent would be yet more flow thin in the

S he ,f; r * *! "^^'^ dubitable, but that there

may be^pknes fo httle elevated nbove the Horizon A B, that the

Teach .k ' 1'" ^^'"^ ' •'^ ^he longeft dme may

^ach the point A, which being to move by the plane A B,an infi-

flof J u.T"''^ ^"^""^ = ^"'^ f'le motion is made always more
»^wiy,by hovv much the declination islefs. It muftbe therefore
to" h r 4 V may be a point taken upon the term B, fo near
the K II ! ^^^^ drawing from thence to the point A a plane,
for not pafs it in a whole year. It is requifitc next

citv the K*ii T' tf^^f 'be namely the degree of velo-

Dninr A r ,^ ^° ^^^^ acquired when it arrivetb at the
Fomt A,is luch,that (houldit continue to move with this felf-famc
grec umtormly,that is to fay ,without accelerating or retarding;

c in

o G. G A L 1 L U S, bis Sjjieme.

mas much more time as it was hi coming by the inclining p^^^^^^
would pafs doable the Ipace of the plane inclined: namely (for
example) if the ball had paft the plane D A in an hour, con-
trnuingti move uniformly with that degree of veloc.ty wh.ch k
i found to have in its arriving at the terin A, U Ihall pafs in an
■ hour a fpace double the length D A and becaufe C have
faid\ the degrees of velocity acquired m the pomts B and A, by
he Moveables that depart from any point taken in the perpend.cu-
ar C B, and that defcend, the one by the inclined plane, the o-
ther by the raid perpendicular, are always equal: therefore the
cadent by the perpendicular may depart from a term fo near to B,
that the degree of velocity acquired in B, would not lufticc (Itill
maintaining the fame) to condua the moveable by a fpace dou-
ble the length o£ the plane inchned in a year, nor m ten, no nor
in a hundi-ed. We may therefore conclude, that if it be true,
that according to the ordinary coutfe of nature a moveable, all
external and accidental impediments removed, moves upon an in-
elinine plane with greater and greater tardity, according as the
inclination ftall be lefs : [o that in the end the tarduy comes to be
• c • ^hich is, when the inclmation concludeth m, and joyneth
To ?h?horizontalplane5 and if it be true Hkewifc, that thedc-
oree of velocity acquired in fome point of the mclined plane, is
o that degree of velocity which is found to be in the move-
able that dcfcends by the perpendicular , in the point cut by a
parallel to the Horizon, which palfeth by that point of the incli-
ning pl^ne j it muft of neceflity be granted, that the cadent de-
parting from reft, paffc-th thorow all the infinite degrees of tar-
dity, and that confcqucntly, to acquire a determinate degree of
velocity, it is neccfTiry that it move firft by right lines, defcend-
ine by a fhort or long fpace, according as the velocity to be acqui-
red ought to be either Icfs or gteater, and according as the plane
on which it defcendeth is more or lels inclined ; fo that a plane
may be given withfolmallincHnation, that to acquire in it the
afliened degree of velocity,it muft firft move in a very great fpace,
and take a very long timci whereupon in the horizontal plane,any
how little foever velocity, would never be naturally acquired,
fince that the moveable in this cafe will never move : but the

1 KniiTontal line, which is neither declined or incli-
The circuUr mn- mouon by the hoiizontai iiuc, wm ^. r ■ .

u never is a tirGulat motioD about thc Centre : therefore the crcu-

T/r«t' lar motion is never acquired naturally, without the right motion
^l^r'C'^^'- precede it i but being once acquired, it will continue perpetually
OrcUr mou^^ r I could .frith Other difcourfes evince and

}r ' demonftrate the fame truth, but I will not by fo great a digref-
llon interrupt our principal argument : but rather wiU return to
it upon fome other occafion j efpecially fjnce we now ^^""^^J^^^^

the
:o B,
(ftiU
dou-
)nor

phe

^neth
lede-
ic, is
move-
by a
incli-
kde.
lar.

of
end-
icqui-
plane

Pine
the
pace,
e^any
uired,
ithe
mdi-

lotion
tually

Ggref-
iirnto.
edthe

Dialogue. I.

feme, not to ferve for a neceOary dcinonftration, but to adorn a
riatontcli Conceit ; to which I will add another particular obfer-
vanon of our Academic^., which hath in it fomcthing of admira^
ble. Let us fuppofe amongft the decrees of the dirine Hrchttea,
a purpofe of creat.ng in the World thefe Globes, which we be-
hold continually moving round, and of affigning the centre of
their converfionsiand that in it he had placed the Sun immoveable,
and had afterwards made all the faid Globes in the fame place,
and with the intended inclinations of moving towards the Centre,

meH '^""^^ °f ^^l^'^i'y' ^J'i^h at firft fee-

we iS r r f^^I^ivineMinde ; the which being acquired,
we laitly fuppofe that they were turned round, each in his Sphere
retaining the faid acquired velocity : it is now demanded, in
S o il^ ""^^ "^'^^""^^ Sun the place was where the

thS, ^"f P"^°"ily created ; and whether it be poffible that
they ™ght all be created in the fame place ? To make this inve-

naln r J f ^'"""^ '""ft ^"^If"" Aftronomers the

magnitude of the Spheres in revolve, and like*

wife the time of .ut-^ revolutions : from which two eogn?t1onS
gathered how much (f for example; J npiur is fwifter than S.-
tHrne , and being found (as indeed it is) that jHfi^.r moves more
fwiftly, It IS requifite, that departing from the fame altitude, 7«.
O K more than ^^^«r«., as. we really know it is, its

Orbe being infenour to that of Satnrne. But by proceeding for-
WL P^o^^i-''^ of the two velocities of J.p Jr and

what altitude and diftance from the centre of their revolutions,

nuagreea upon, it is to be fought, whether Wrs dctcevi^iaz^'i'cujlf thcn«.
worn thence to his Orb, the magnitude of the Orb, and the ve- ""'^

tSn'^ T"??' ^P''^ "^''^ ^•'^ -^^''^ fo""d by calcula- t:^^

tion , and let tile like be done of the Earth, of Vcn^, and of"'
Mercury ; the greatnefs of which Spheres, and the velocity of
is ver^XiTablf^'^ fo nearly to what computation gives, that it

S A G R. 1 have hearkened to this conceit with extreme delight;
and, but that I believe the making of thefe calculations truly
would be a long and painfull task, and perhaps too hard for me
lo comprehend, I would make a trial of them.

ALv The operation indeed is long and difficult ; nor could
1 oe certain to findc it fo readily ; therefore we fliall refer it to an-
ner time, and for the prefent we will return to our firft propo-
going on there where we made digrefllon j which, if I well
member, was about the proving the motion by a right line of no

C a Hfei

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

20 G. G A L I L u s. Us Syftcme.

ufe, in the ordinate parts of the World j and we did proceed to
Tay, that it was not fo in circular motions, of which that which is
made by the moveable in it felf, ftill retains it in the fame place,
Finite and termi- jf^j^j. vvhich catrieth the moveable by the circumference of a
ZZ Zfo!der Z't circle about its fixed centre, neither puts it felf, nor thofe about it
the parti of the difordci, for that fuch a motion primarily is finite and terniiinate
(^though not yet finiflied and determined) but there is no point
In the circular mo- the circumfcrencc, that is not the firft and laft term in the cir*
1h? llrclSfJ'lnce cuUtion *, and continuing it in the circumference affigned it, it
is'theL7tZn^and Icavcch all the reft, within and without that, free for the ufc of
others, without ever impeding or difordering them. This being
a motion that makes the moveable continually l«^ye, and-con-
Circular motion tinually arrivc at the end , it alone therefore can primarily be u-
•w// is uniform, jjiform j for that acceleration of motion is made ia the moveable,
when it goeth towards the term, to which it hath inclination i
and the retardation happens by the repugnance that it hath to
leave and part froni the lame term , and becaufe in circular mo-
tion, the moveable continually leaves the natural term, and con-
tinuaHy movotK towards the fame, therefore, in it, the repug-
nance and inclination are always of equal force : from which e-
quahty refults a velocity, neither retarded nor accelerated, i. e. an
uniformity in motion. From this conformity, and from the being
Circular motion terminate, may follow the perpetual continuation by fucceffively
ma;Se continued ^citcT2itinQ^ the circulatious 5 which in an undeterminated line,
perpetually. ^ motiou Continually retarded or accelerated, cannot ria-

%ightwo:ioncaK-mv2\\yh^, I fay, natutally^ becaufe the right motion which is
Mt naturaiij he retarded, is the violent, which cannot be perpetual ^ and the ac-
perpetuai. celcrate arrive th neceffarily at the term, if one there be ^ and if
there be none, it cannot be moved to it, becaufe nature moves
not whether it isimpolTible to attain. 1 conclude therefore, that
the circular motion can onely naturally confift with natural bo-
dies, parts of the univerfcjand conftituted in an excellent difpo-
fure i and that the right, at the moft that can be faid for it, is
Right motion af- ^/Tgj^p J ky naturc to its bodies, and their parts, at fuch time as

ftfrncd to natural "^J r i • l /I ^ J • J i

bodies , to reduce they lhall be out of their proper places, conltttuted m a depraved
themto perfcB or- Jifr^ofi tinu, and for that caufc needinj^ to be redurcd by the fifiort-

der^when removed. '^^^J:'^^^'-**^^ ? , . . .

from their places, eft way to thcit natural ftate. Hence, me thmks, it may ratio-
nally be concluded, that for maintenance of perfcft order amongft
the parts of the World, it is neceifary to lay, that moveables are
moveable onely circularly ^ and if there be any that move not
'K^f^W;,-^^ circularly, thefe of neceffityare immoveable : there being no-
circuiar motion are thi^a but reft and circular motiou apt to the confcrvation of or-
ajt^toconferveor^ ^^^^^ And I do not a Uttlc wondcr with my felf, thn Arifiotle,
who held that the Terreftrial globe was placed in the centre of
the World, and there remained immoveable, fliould not fay, that

th is
lace,
of a

nate
)bint
^ cir*
[t, it
fcof
»efHg
con-
^ u-
Me,
fion V

:h e-
e. an

Dialogue. I.

are moveable by naturcj and others immo-
ore defined Nature, to be the prin .

of natural bodies fome are
veable ; cfpecially having
ciple of Motion and Reft.

SiMV L. Ariftotle, though of a very perfpicacious wit, would
f^^rther than needed : holding in all his argumen-
tatKHis, thatlenfiblc experiments were to be preferred before
any realons founded upon ftrcngth of wit, and faid thofe which
Ihouia deny the teftimony of fefife deferved t<) be punifticd with
the lols ofthat fenfe , now who is iix blind, that fees not the
parts of the Earth and Water to move, as being grave, natural-
iy downwards, namely, towards the centre of the Univerfe af-
ligned by nature her felf for the end and term of right motion
deorfum; and doth not lik^wife fee the Fire and Air to move
right upwards towards the Concave of the Lunar Orb, as to thd
natural end of motion/Hr/«;« ? And this being fo mauifeftly feen,
and we be,ng certain that e^em eBratto toLs d^partmm, why
may we not alFert it for a true and manifrft propofiL, tha't the
natural motion of the F.^.-*'- - "S°>- —ci^JT ' !

that of the Fire- nglit d modio i.',^~ y.. and
SAI.V. The moft that you camprefcnd from this your Dif-
courfc, were It granted to be true, is that, like as the parts of tL
Earth removed from the whole, namely, from the place where
they naturally reft, that is in (hort reduced to a depraved and dif.
ordered difpofure, return to their place fpoataneoufly, and there-
fore naturally in a right motion, (itbeing granted, that

ler eftrial Globe removed violently from -the place affigned
It by nature, ,t would return by a right line. This, as I have
laid, ,s the moft that can be granted you, and that onely for want
ot examination ; but he that Hiall with exadnefs rcv.fe thefe
things, Will hrft deny, that the parts of die Earth, in returnine to
Its whole, move in a right line, and not by a circular or mixt ; and
reauy you would have enough to do to demonftrate the contra-
ry, as you (hall plamly fee in the anfwers to the particular reafons
and experiments alledged by P^olomey zr^d AnftotU. Secondly,
It another fliould fay that the parts of the Earth, go not in their
motion towards the Centre of the World, but to unite with its
*yh0lc,znA that for that reafon they naturally incline towards the
centre of the Terreftrial Globe, by which inclination they con-
P're to form and prelervc it, what other AU, or what other Centre

nK ^""^ ' "^^'^^ Terrene

Olobe, being thence removed, would feek to return, that fo the

zMA ^'^"^^ '"'S''^ ''■'^ ^° ^'"^ P"'*' ^ *t may be

aued. That neirher AriftotU, nor you can ever prove, that the
arth de faSio is in the centre of the Univerfe; but if any Centre

may

Senjihle expert'
mentsare to he pre*
ferred before hw
mane Argtimenta-
tiofis.

He who denies
fenfe^ deferVfs t§
i'e deprived of it,
Senfe jhemeth thdt
things grave move
to f^tf medium, and
the light te the
concave.

It is (jueflionahU
T^hetherdefcending^
rf eights move in 4
rf^ht line.

The Earth Iferi-
cat yj con^i.^
ration of its parts
to its Centre,

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

21 G. G A L I L ^ u s, hiiSyfteme.

rhSunm^repro'imy bc affigncd to the Univerfc, we ftiall rather find the Sun
lf!hc%ZTrl placed in it^ as by the fequel you fliall undcrftand.
th^JthcEanhV' Now, like as from the confentaneous confpiration of all the
parts of the Earth to form its whole, doth follovVj that they with
Nattitd iKcit»A' equal inclination concurr thither from all parts h and to unite
tion of the parts of themfelvcs as much as is poflible together, they there fphciically
fbe mrfto'go '[adapt themfelves i why may we not believe that the Sun, Moon,
their centre. ^nd other mundane Bodies, be alfoof a round figure , not by o*
ther than a concordant inftinfi, and natural concourfe of all the
parts eompofing them ? Of which, if any, at any time, by any
violence were feparated from the whole , is it not reafonable to
think, that they would fpontaneoufly and by natural inftinS: re-
turn ? and in this manner to infer, that the right motion agreeth
with all mundane bodies alike. ; .

SrMPi.* Certainly, if you in this manner deny not onely the
Principles of Sciences, but manifeft Experience, and the Senfes
themfelves, you can never be convinced or removed from any o-
pinion which you once conceit J therefore I will choofe rather to
bc filent C^c^tj contra negantes principia non eft difputandnm)
than contend with you. And infifting on the things alledged by
you even now (fince you queftion fo nmch as whether grave move-
ables have a right motion or no) how can you ever rationally dc-
The ri^ht r>fotion ^y, that the parts of the Earth , or, if you will, that ponderous
«»/ grave bodies ^^^^^-ers dcfccnd towatds the Centre, with a right motion j when-
mantfefitofenfe. ^^^^^ ^ ^^^^ high Towcr, whofe walls are very upright and

perpendicular, you let them fall, they (hall dcfcend gliding and
Aiding by the Tower to the Earth , exaflly in that very place
where a plummet would fall,being hanged by ahnefaftned above,
juft there, whence the faid weights were let fall > is not this a
more than evident argument of the motions being right, and to-
r^odrT^r.^"^ wards the Centre ? In the fecond place you call in doubt, whe-
Watlrav'^e bodies thet thc parts of the Earth are moved, as Anftotle affirms, to-
move with a» in- ^^^^^^ ^j^^ Centre of the World i as if he had not rationally de-
TtZTeme7'tZ mo^^ whilfthethus argueth -, The

Vmverfe. motion of hcavic bodies is contrary to that of the light : but thc
motion of the light is manifeft to be direftly upwards , namely,
towards the circumference of thc World, therefore the motion of
the heavie is dire&ly towards the Centre of the World : and it
j{eavie bodies happens per accidens^ that it be towards the centre of the Earth,
TeZlJoTthlEal^h ^^^^ ^his ftriveth to be united to that. The fecking in the
l[7zcadJs. ' next place, what a part of the Globe of the Sun or Moon would
do, were it feparated from its whole, is vanity *, becaufe that there-
To feek w^^^ by that is fought, which would be the confequence of an impoffi-
tPOHid follow p*pon i^.j.^^ . .^^ regard that, as Ariftotle alio dcmonftrates, the coeleftial
folly. bodies are impaflible, impenetrable, and infrangible • fo that fuch

a cafe

»on,
^ o-

}US

us a
I to-

lere-
ftial

Dialogue L'
a cafe can never happen: and though it fliould, and that the fe-

parated part Ihould return to its whole, it would not return as neither hiavte mr
grave or light, for that the fame Arijiotle provcth, that the C(£- ^^^f^J^-j^^^^^^^
Icftial Bodies are neither heavie nor light. ^

S A L V. With what reafon I doubt, whether grave bodies move
by a right and perpendicular line, you ftall hear, as I faid be-
fore, when I lhall examine this particular argument. Touching
the fecond point, I wonder that you fliould need to difcover the
Paralogifm of Ariftotle^ being of it fclf fo manifefi ^ and that
you perceive not, that AnftotU fuppofeth that which is in quefti-
on : therefore take notice.

Sim PL. Pray Sahiatns fpeak with more refpefi of Arijioth:
for who can you ever perfwade, that he who was the firjft, only,
and admirable explainer of th^SyUogiflick forms of demonfrration, Arii^ode cannot
oiElenchs.oi the manner of difcovering5(7pfc//ii;/j',r4r^%//«j',aLd IhJ'Z^''' ^J^^
m (hortjof all the parts of L(?^i4,fliould afterwards fo notorioufly 'a^C*'"'
equivocate in impofing that for known, which is in queftion ? It
would be better, my Mafters, firft perfedly to underftand him,
and then to try, if you have ^ 'T '^'^V him.

Salv. Simpli-^;^^ ^^/^e here familiarly difcourfing among
our fcives, to inveftigate fome truths I (hall not be difpleafed
that you difcover my errors , and if I do not follow the mind of
Arijiotle, freely reprehend me, and 1 fliall take it in good part.
Onely give me leave to expound my doubts, and to reply fome-
thing to your laft words, telling you, thsit Logic l^, as^it is well
underftood, is the Organe with which we philofophate , but as it
may be poffible, that an Artift may be excellent in making Or-
gans, but unlearned in playing on them, thus he might be a great
Logician, butunexpertinmakingufeof L<?^i/:^S like as we have
many that theorically underftand the whole Art of Poetry , and
yet are unfortunate in compofing but meer four Verfes j others 'A famous /M/r/«
en;oy all the precepts of t^ifjci* , and yet know not how to paint fainter,
a Stoole. The playing on the Organs is not taught by them who
know how to make Organs, but by him that knows how to play
on them : Poetry is learnt by continual reading of Poets : Limn-
ing is learnt by continual painting and deligning : Demonftration
from the reading of Books full of demonftrations, which are the
Mathematical pnely, and not the Logical. Now returning to our
purpofe, I fay, that that which Arijiotle feeth of the motion of
%ht bodies, is the departing of the Fire fro^^ ^ny pajt of the
Siiperficies of the Terreftrial Globe, and dir^ftly retreating from
It 5 niounting upwards ^ and this indeed is to move towards a
Circumference greater than that of the Earth j yea, the fame A-
rijlotU mzliQs it to move to the concave of the Moon, but that
this circumference is that of the World, or concentrick to it, fo

that

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

Tavalogifmof A-
riftotle, $tj proving
the Earth to he in
the Centre of the

mrid.

The VdrMlbgifme
c/ArUiodc another
vto) dtfcovered.

G. G A L I L ^ u his Syjleme,

that to move towards this, is a moving towards that of the World,
that he cannot affirm, unlcfs he fuppofcth, That the Centre of the
Earth, from which we fee thefe light alcendent bodies to depart^
be the fame with the Centre of the World ^ which is as much as
to fay, that the terrefirial Globe is coiiftituted in the midft of the
World : which is yet that of which we were in doubt, and which
AriBotle intended to prove. Atid do you fay that this h not a
manifeft faralogifm ?

Sagr. This Argument of ^ri/?of/e appeared to me deficient
alfo, and w<?«-concludent for another refpeft though it were
granted, that that Circumference, to which the Fire dircfily mo-
veth, be that which includeth the World : for that in a circle,
not onely the centrcjbut any other point being taken^every move-
able which departing thence, fhall move in a right Hne, and to-
wards any whatfoever part, fliall without any doubt go towards
the circumference, and continuing the motion, fhall alfo arrive
thither h fo that wc may truly fay, that it moveth towards the
circumference : bur yet it doth not follow, that that which mo-
veth by the fame line with a contrary motion, would go towards
the centre, u^lc^^ when the point taken were the centre it fclf,
or that the motion were made by that onely line, which produced
from the point affigned, paffcth thorow the centre. So that to
fay, that Fire moving in a right line, goeth towards the circumfe^
rencc of the World, therefore the parts of the Earth which by
the fame lines move with a^ contrary motion, go towards the cen-
tre of the World, concludeth ret , unlefs then when it is pre-
fuppoied, that the lines of the Fire prolonged pafs by the centre
of the World ^ and becaufe we know certainly of them, that they
pafs by the centre of the Terrefirial Globe (being perpendicu-
lar to its fuperficies, and not inclined ) therefore to conclude, it
mufi be fuppofed, that the centre of the Earth is the I'ame with
the centre of the World , or at lea ft , that the parts of the Fire
and Earth defcend not, fa ve onely by one fole line which pciffeth
by the centre of the World. Which neverthclefs is falfe, and re-
pughant to experience , which ftieweth us , that the parts of
Fire, not by one line onely, but by infinite, produced from the
centre of the Earth towards all the parts of the World, afcend
always by lines perpendicular to the Superficies of the Terrejtfei-
al Globfe.

S alv. You do very ingenioufly h^d Anfiotle to the fame in-
convenience, Sagredm J (hewing his manifeft equivoke j but
withal you add another inconfiftency. We fee the Earth to be
fpherical, and therefore are certain that it hath its centre, to which
we fee all its parts are moved ^ forfo'we mnft fay, whilfi their
motions are all perpendicular to the Superficies of the Earth h we

mean,

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

tvt
lo^
ble,
[fove-
d to-

Ifrive

ts the
1 mo-
wards
: felf^
duced
liac to
Lunfc-

!Mtre
: they
idku-
de, it
with
? Fire
jflfeth

M of

ii the
fcend

sn-

9Ut

vhich
their
) we

Dialogue. L

in-ean, that as they move to the centre of the Earth, they move t6
thnv IHoUy and to their Univerfal Mother : and we arc ftill far-
ther fo free, that we will fufFer our felves to be perfwaded, that
their natural inftinft is, not to go towards the centre of the Earth.

tind, or whether it be or no 3 and were it granted to be, it is but c.^.r. ./ th.
an imagmary pomt, and a nothing without any quality. As to f,^^.'^' f^-""/^^'
u^.at S..plm.s faid laft, that the contending Whether the parts ""^'^
thnfl n'^'^'' ^^^y^ feparated from their

h\^t^Z '"'u''''"^ ''^ " the cafe •

IS impoffible , It being clear by the Demonftrations of Anjiotle,

T/t T^'r ^f'' -^^pMc, impenetrable, unparta- W
./ 1 anlwer, that none of the conditions, whereby AriHo- ^kicb

tffo3:5:?.£' Co.left.al Bodie. from Elementary; hatho-
tfter toundafon than what he deduceth from the diverfity of the n,c.arW.d.r.

affirmed tLt [tSfa,r"eT'^^^

is behoofull upon f cc'^ary confequence to fay, eitheTtha 'ehe
attributes ot gencrable, onngenerable, alterable, or unalterable

^n" f^,°'LT"'^'''^'- ^I'^'^y «onIy agree with
all worldly bodies, namely, as well to the Coelcftialas to the E-
kmcntary i or that AriftotU hath badly and erroneoufly dcdu-
leftial BodieT ' y\ach\it hath affigned to Coc-

on o^al?NI^'^T^'^ °[ "^g'^^^^io" ^^n^s to the fubverfi-
of »ell *^^''°^°P''y' to the diforder and fubverfion

of Heaven and Earth, and the whole Univerfe ; but I beheve the
Fundamentals of the f rrif .^.^zc^. are fuch , that we need not
icar that new Sciences can be ereaed upon their ruines.

• L ^ r' ^^''^ "° thought in this place for Heaven or the Earth,
neither fear their fubverfion, or the ruinc of Philofophy. As to
nS'" ir"^ ^hat which you your felf hold

unalterable and nnpaffible ; as for the Earth, we ftrive to enoble
and pcrfea it , whilft we make it like to the Coclcftial Bodies,
and as It were place it in Heaven, whence your Philofophers have
iSutes '[°^*'P''y f^lf <=annot but receive benefit from our n,.,^«,„w

H'uicsjior It our conceptions prove true, new Difcoverics will """r'i-aicm »/

Rath I'/ '""•■^ confirmed, .^^tj^^t"

M a Z^"""' y^""" '^are upon fome Philofophers, and help and ''""fi">f

AndfK ' *° ^"^"'^ '"^ ""no*^ improve.

wnat prelents it felf to you in confirmation of that great dif-
crence which Arifiotle puts between theCocleftial Bodies, and
fclcmcntary parts of the World, in making thofc ingenerable,

D incor-

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

z6 G, G A L 1 L ^ u bis SjlJeme.

incorruptible, unalterable,c^f . and this corruptible, alterable^c^r.

S iMPL» 1 fee not yet any need that AriftotU hath of help,
ftandii\g as he doth ftoutly and ftrongly on his feet , yea not be-
ing yet affaulted, much lefs foiled by you. And what ward will
hx'Mtsdtfconrfe you choofe in this combate for this firft blow > Ari^iotle wrlteth,
to prove the wcor- that whatevcr is generated, is made out of a contrary in fome
ruptthtUtyofHe^' ^^j^j^^^ likewifc IS Corrupted in fome certain fubjecl from a
generation & cor- contrary into a contrary , fo that (obferve) corruption and ge-
ITi'^^^ trrti^', neration is never but onely in contraries ^ If therefore to a Coe-
accord:»^ loArift! leftial Body no contrary can be affigned, for that to the circular
To the circular motion 120 Other motion is contrary, then Nature hath done very
motion no other ^akc that cxempt from contraries, which was to be in-

motion xscomrarj. incorruptiblcj This fundamental firft confirmed,

it immediately fqilowetli of confequence, that it is inaugmenta-
ble, inalterable, impaflible, and finally eternal, and a propor-
^!ZJJ*lbel^' tionate habitation to the immortal Deities, conformable to the
mortal God!. opinion even of all men that have any conceit of the Gods. He
H^~JS/^^f^™^d^^^^^^ b^^enfe; in regard, that in all

fe^fe. times paft, acfor^iing to memory or tradition, we fee nothing re-

mov^a, according to the whole outward Heaven, nor any of its
/r.pr.t..r^r^4t proper parts. Next, as to the circular motion, that no other is
the circular motion contrary to xu Ari^iotle provcth many ways , but without reci.
kath no contrary, ^j^^ ^hem all, it is fufficieutly dcmonftratcd, finccfimple motions
are but three, to the medium^ from the medmnty and about the
medium^ of which the two right, furfum and deorfum, are mani-
feftly contrary h and becaufe one onely hath onely one for con-
trary, therefore there refts no other motion which may be contra-
ry to the circular. You fee the fubtle and moft concluding dif-
courfe of AriftotU:, whereby he provcth the incorruptibihty of
Heaven.

S A L V- This is nothing more, fave the pure progrefs of Arifto.
tle^ by me hinted before h wherein, befides that I affirm, that the
motion which you attribute to the Coeleftial Bodies agreeth alfo
to the Earth, its illation proves nothing. I tell you therefore,
that that circular motion which you affign to Coeleftial Bodies-
fuiteth alfo to the Earth, from which, fuppofing that the reft of
your difcourfe were concludent, will follow one of thefe three
things, as I told you a little before, and fhall repeat^ namely,
either that the Earth it felf is alfo ingenerable, and incorruptible,
as the Coeleftial bodies^ or that the Coeleftial bodies are, like as
the Elementary generabic, altemble &c. or that this difference of
motion bath nothing to do with Generation and Corruption.
The difcourfe of Arijiotle^ and yours alfo contain many Propofi-
tions not to be lightly admitted, and the better to examine them,
1% will be convenient to reduce them to the moft abftrafted and

diftina

lOt be-
d will
riteth,
Hbme
wbm a
id ge-
i Coe-
Tciriar
e very
be in-
inned,

por-
ro the
s. He

of its

fer is
frcci.
tions
lit the
fcani-
rcon-
wjtra-
ig dif-
ey of

I and

Dialogue.^ I. ij
difiinatlutcan bepolllblci and excufe me Sagredm, if haply
with fome tcdioufnefs you hear me oft repeat the fame things,
and fancie that you fee me reaffume my argument in the pub-
liclc circle of Difputa tions. You fay Generation and Corrupti-

are onely amongft fimple natural bodies, moveable with contrary
motions ; coatriry motions arc onely thofe which are made by
a right line between contrary terms; and thefe are onely two,
that IS to fay from the medium, and towards the mcdinm ; and
mch motions belong to no other natural bodies, but to the Eartk

and r?' ' ^'^'"^'^^^ ^''"^fo^^ Generation

th.X aT'T " ^«*°"gft Elements. And becaufe

nc third fimple motion, namely, the circular about the vtcdinm,

onelv"L?hT"^' «^ contraries, and one

v^th whfch f body
no con^arv^^^^^^ ^^"^^^ ^"""^'X ' having

th^?e is nT B^''"^- where

••"cre 19 no contrarietv thf *- ge*.^...^ ^ ^^^^ . ,

But fuch motion »"a^feo.dy with the CceleftTalSrehJ;:
fore onely thefe are ingenerable, incorruptible, And to /'"-A^

begin I think ,t a more eafie thing, and fooner done to;^?olvl t^r'""^"''
whether the Earth (^a moft waft r^j„ Jf • • • . *"*^> '*'««^««r»wf'i'-

u ion about us own axis m twenty four hours would be, than it

g Silrco ^'^^ -'^"fa-^here befuch things a"
KZ^ ' '°""P"°'' ^'"^ contrariety in nature. And if Lw

Zn lZnT r ""''" ""'^^'^ Nature obferves in w^ng,'
When Ihe m a very ftort time begets an infinite number of flif
from a httle vapour of the Muft of wine, and can fhew me which
aldt"' '^rr'^fl'- r ^^'^ « - thatcorrSpte h,

I'tkZL^^""^'^ ''^'f ^"'^''^ '^'^ "'^^^ 'han I can ; for I
Z Za! "T'^'*""?'"'^'"'' ^''^fe things. Bcfides, I would ve-
fofa f^uf '^^"^^^"'^"'^-''y^heflcorruptivec^^^^^^
fo favourable to Daws, and fo cruel to Doves ; fo indulgent to

mofe've"a V" "°^^"> '^^y g""^ to them^nany

P. J. J 7 Jl^"' °^ i°«rniptibaity, than weeks to thefe.

reaches and Olives are planted in the fame foil, «pofed to the
^ me heat and cold, to the fame wind and rai>«s, and, in a word
and thir "1^ contrarieties ; and yet thofe decay in a Ihort time*
thoroww Z^^Tl ''""^"'^ y^"'- F"''hermore, I never was
iL °S"^''fi^'l^boutthisfubftantiaI tranfmutation (ftiU keep-

tSa^^'ru"^''''^^^'''''''^'^ whereby a matter becometh fo
Z fnrZ ' ^""'-^ be neceffarily faid to be deftroy'd, fo

nothmg remameth of its firft being, and that another body
D a quite

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

[en

2g G. GALlLiEUS, fcfxSj/^^W^.

BrntrarWiionamt^ difFering therefrom fliould be thence produced ^ aixi If I
^ parts r^ayrtpre- r a bodv Under ouc afpeft, and by , and by under

W hd:es under ^ J ^ ..^ . i - i • • mUl^ U..^

MverfealyMs, ano

ther very different, 1 cannot think it impolTible but that it may

happen by a fimple tranfpofition of parts, without corrupting or
ingendring any thing a-new , for we fee fuch kinds of Metamor-
phofes dayly : fo that to return to my purpofe, I anfwer you,
that inafmuch as you go about to perfwade me that the Earth cau
not move circularly by way of corruptibility and generabihty,
you have undertook a much harder task than 1 , that with argu-
ments more difficult indeed, but nolefs concluding, will prove
the contrary.

S AGR. Pardon mc, Sahiatus^ it I interrupt your difcourfe,
which, as it delights me much, for that I alfo am graveled with
the fame doubts , fo I fear that you can never conclude the fame,
without altogether digrcfling from your chief defign : therefore
if it be permitted to proceed in our firft argument, I fliould think
that it were convenient to remit this queftion of generation and
corruption to anotW dimndi and Tingle conference as alfo, if
it fliaJI pleafc y^^ SimpliciHS, we may do by other particulac
queftions which may fall in the way of our difcourfe h vi^hich I
will keep in my mind to propofc, and cxaftly difcufs them fome
other time. Now as for the prefent, fince you fay , that if Ari^
ffW^^ deny circular motion to the Earth in common with other
bodies Caeleftial, it thence will follow, that the fame which be-
falleth the Earth, as to its being generablc, alterable, will
hold alfo of Heaven, let us enquire no further if there be fuch
things in nature, as generation and corruption, or not ^ but let;
us return to enquire what the Gtebe of the Earth doth.

S I M P L« I cannot fuffer my cars to hear it quetiion'd, whether
generation and corruption bc in rcrnm natura^ it being a thing
which we have continually before our eyes , and whereof A riftotU
^'^'yj^.'lll^^l hath written two whole Book^j But if you go about to deny the
r« 'p^'^'^''^ Principles of Sciences, and queftion things moft manifeft , who
may hmawtam- fcuows not, but that you may prave what you will, and maintain
any Paradox ? And if you do not dayly fee herbs, plants, ani-
mals to generate and corrupt, what is it that you do fee ? Alfo,
do you not continually behold contrarieties contend together,
and the Earth change into VVater^ the Water turn to Air, the
Air into Fire, and again the Air to condenfc into Clouds, Rain^,
Hails and Storms > /r/

SaGR. Yes, wc fee thefc thitigs indeed, and therefore will
grant you the difcourfe of Arijlotle^ as to this part of generation
and corruption made by contraries h but if 1 fliall conclude by
virtue of the fame propofitions which are granted to Arifiotle,
that the Coeleftial bodies themfelvcs are alfo generable and cor-
ruptible

id.

Dialogue I*

gdcr

for
nor-
^u,

^an

ility,
rgu-

Ith
le,

Jforc
think
I and
fo, if
^ulai
lich I
fomc
Art^
other
I be*
will
fuch
it let

thing
tftotU
y the
who
ain
mi-
fo,

the

I will
ation

the Elementary
fay you h

what will you fay then

done that which is itnpoffible to

rupdble, afwell as
SiMPL. I will
be done.

SAGR. Go toi tell me, Simpltcim^ are not thefc afFeftions
contrary to one another ?
SIM PL. Which?

SAGR. Why thefc; Alterable, unalterable, pafflblc, ''impaf- *0'->l™P*^i^l«*
fible^ generable, ingenerable, corruptible, incorruptible ?
S I M p L. They are moft contrary.

S AGR. Well then, if this be true, and it be alfo granted,
that Coeleftial Bodies are ingenerable and incorruptible; I prove
that of neceffity Coeleftial Bodies muft be gcnerable and corru-
ptible.

S I M P L* This muft needs be a Sophifm.

Sagr. Hear my Argument, and then cenfure and refolve it. ^^^^^-^i^^^^^^
Coeleftial Bodies, for that they are ingenerable and incorruptible,

are gcnerablt and

have in Nature their contraries, which are thofe Bodies that hc'orrupMe, hc-^

111 .1 caHie tnej are t»'

cTfrifrahi** r^t^A . L — ^^••'^ «s contrancty, there

therefore Coeleftial Bodies arc corrupt tbU,

gcnerable and corruptible -
is alfo generatior. corruption ;
gcnerable and corruptible.

S I MPi. Did 1 not fay it could be no other than a Sophifm >
This is one of thofe forked Arguments called Sorita : like that The forked Syfb^
of the Cretan^ who faid that zWCretdus were lyars; but he aiss'M^^^'d:^,»}nf^
being a Cretan^ had told a lye, in faying that the Cretans were ly-
ars ; it followed therefore, that the Crr^^j/rj' were no lyars, and
confequently that he, as being a Cre^^j/i, had fpoke truth : And
yet in faying the Cretans were lyacs, he had faid true, and com-
prehending himfelf as a Cretan^ he muft confequently be a lyar.
And thus in thefc kinds of Sopbifmssi man may dwell to eternity,
and never come to any conclufion.

SagR. You have hitherto cen£urcd it, it tenuincth now that
you anfwer it, (hewing the fallacie.

S I M p l: As to the refolving of it, and finding out its fallacie,
do you not in the firft place fce a manifeft contradiflio^i in it ?
Coeleftial Bodies are ingenerable and incorruptible ; E^i^i Ccelc-
ftial Bodies are gcnerable and corruptible. And again, the gon- AmongfiCaUftiai
trariety is not betwixt the Coeleftial Bodies, but betwixt the E- ^ ^

fcments, which have the contrariety of the MotionSj Jnrfkm and
dc€rfhm, and of levity and gravity But the Heavens which move
circularly, to which motion no other motion is contrary, want
contrariety, and therefore they are incorruptible.

Sagr. Fair and foftly, SimplteiuS', this contrariety whereby
you fay fome fimple Bodies become corruptible, refides it in the
fame Body which is corrupted, or elfe hath it relation to fome o-
Qther ? \ fay, for example, the humidity by which a piece of Earth

comrarttfjf.

jQ C. G A L I L ^ u s, his Syfleme.

is corrupted, refidesitin the fame Earth or in fomc other bodie,
which muft either be the Air or Water ? I beUeve you will grant,
that like as the Motions upwards and downwards, and gravity
and levity, which you make the firft contraries, cannot be in the
fame Sub)ea,fo neither can moift and dry, hot and cold : you
muft therefore confequently acknowledg that when abodic cor-
Cntrariis .hich rupteth, it is occafioncd by fome quality rcfiding in another con-
sre the cAufes of . therefore to make the Coeleftial Body become

corruptible, it fufficeth that there are in Nature, bodies that have
dytkAtcorrHptcth, ^ contrariety to that Coeleftial body h and luch are the Elements,
if it be true that corruptibility be contrary to incorruptibility.

Sim PL. This fufficeth not. Sir j The Elements alter and cor-
rupt, becaufe they are intermixed, and are joyn'd to one another,
Car/.y?«vi/W/« and fo may exercife their contrariety i but Coeleftial bodies are
touch, but are not ff om the Elements, by which they are not fo much as

Tf^m^^ ^' toucht, though indeed they have an influence upon the Elements.

It is requifite, if you will prove generation and corruption in Coe-
leftial bodies, that you fliciv j Chat there refides contrarieties be-

tween^hem.^^ how I will find thofe contrarieties between them.
The firh fountain from whence you derive the contrariety of the
Elements, is the contrariety of their motions upwards and down-
wards it therefore is neceliary that thole Principles be in like
Grdvity& levity, ^g^tiVi^i coutrarics to each other, upon which thole motions dc-
fAritj and df^^Jj^^^ pend and bccaufe that is moveable upwards by hghtnefs,
4rf^c.«tMr7 ^j^.^ downwards by gravitv, it is nccelTary that lightnefs and

gravity are contrary to each other : no Icfs are we to believe thofe
other Principles to be contraries, which are the caufes that this is
heavy, and that light : but by your own confeffion, levity and
gravity follow as confequents of rarity and denfity therefore
r^./^,,«M./^ rarity and denfity fliall be contraries : the which conditions or
fnrpafs the fmh^ afFeftions ate fo amply found in Coeleftial bodies, that you c-
^Helvfnt'delftf ftats to be oncly more denfc parts of their Heaven:

njttj. ^^^^ foUoweth that the denfity of the ftars exceeds

that of the reft of Heaven , by almoft infinite degrees :
whichismanifeft,in that Heaven is infinitely tranfparent, and
the ftars extremely opacous j and for that there arc there above
no other qualities, but more and lefs denfity and rarity , which
may be caufes of the greater or lefs tranfparency. There being
then fuch contrariety between the Coeleftial bodies, it is necelfary
that they alfobc generablc and corruptible, in the fame manner
as the Elementary bodies arc h or clfe that contrariety is not the
Rarity & derSttj caufc of Corruptibility, (^c.

inCeehf^iaibodies, § I M P L- There is no neceffity either of one or the other , for
l^f'r^^^- that denfity and rarity in Cceleftial bodies, are not contraries to

each

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

Dialogue L"

ant,

lie
»u

ome
have

€or-
cuts.

1;^

s de-
cnefs,
s and
thofe

n$ or

each other, as in Elementary bodies i for that they depend not
on the primary qualities, cold and heat, which are contrariesj but
on the more or Icfs matter in proportion to quantity : now much
and little, fpeak onely a relative oppofition, that is,. the. leaft of
oppofitions, and which hath nothing to do with generation and
corruption.

Sag R- Therefore affirming, that denfity and rarity, which a-
mongft the Elements fhould be the caufe of gravity ^nd levity,
which maybe the caufes of contrary motions furfkm and dear*
fkm^ on which, again, dependeth the contrarieties for generation
and cormption ^ it fufficeth not that they be thofe denfneffes and
rareneffcs which under the fame quantity, or (if you will) mafs
contain much or little matter, but it is neceifary that they be denf-
neffes and rareneffes caufed by the primary qualities, hot and
cold, otherwife they would operate nothing at all : but if this be
fo, Ariflotle hath deceived us, for that he ftiould have told it us at Ariftode defeaive
firft, and fo have left written that thofe fimple bodies are gene- 'LffjJh/ct

rable and corruptible tha;^ — "^^th {imple moiioDS ,»e„ts are gertera-

upwards and dow— dependent on levity and gravity, cau- I'i^ & crrr^p^M.
fed by rarity and denfity, made by much or little matter , by
reafon of heat and cold j and not to have ftaid at the fimple mo-
tion furfum and deorfum : for I affure you that to the maidng
of bodies heavy or light, whereby they come to be moved with
contrary motions, any kind of denfity and rarity fufficeth, whe-
ther it proceed from heat and cold, or what elfe you pleafc ^ for
heat and cold have nothing to do in this affair : and you fhall
upon experiment find, that a red hot iron, which you muft grant
to have heat, weigheth as much, and moves in the fame manner
as when it is cold. But to overpafs this alfo> how know you but
that Coeleftial rarity and denfity depend on heat and cold ?

Sim PL. I know it, becaufe thofe qualities are not amongft
Coeleftial bodies, which are neither hot nor cold.

S A L V- I fee wc arc again going about to cngulph our felves in
a bottomlcfs ocean, where there is no getting to ftiore h this
is a Navigation without Compafs, Stars, Oars or Rudder : fo that
it will follow either that we be forced to pafs from Shelf to Shelf,
or run on ground, or to fail continually in danger of being loft.
Therefore, if according to your advice we fliall Proceed in our
n^ain defign, wc muft of ncceffity for the preicnt overpafs this
general confideration, wh^her direamotioP be neceffary in Na-
ture, and agree with fome bodies and come to the particular
demonftrations, obfervations and experiments h propounding in *
the firft place all thofe that have been hitherto alledged by Arh
ftotU, Ptolomey, and others, to prove the ftability of the Earth, en-
deavouring in the next place toanfwer them : and producing m

the

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

p G. G A L I L ^ u s, Syjiane.

the laft place, thofe,by which others may be perfwaded, that the
Earth is no lefs than the Moon, or any other Planet to be num-
bered amongft natural bodies that move circularly.

SAGR. 1 fliall the more wiUmgly incline to this, in that I am
better fatisfied with your Architeaonical and genera] difcourfe,
than with that of ^r//^?f/e, for yours convinceth me without the
leaftfcruple, and the other at every ftep croffcth my way with
fome block. And 1 fee no rcafon why Simflicins Ihould not be
prefently fatisfied with the Argument you alledg, to prove that
there can be no fuch thing in nature as a motion by a right line,
if we do but prefuppofe that the parts of the Univerfe are difpo-
fed in an excellent conftitution and* perfeft order.

S A L V. Stay a little, good Sagredus^y for juft now a way comes
into my mind, how I may give SimpliciHS fatisfaflion, provided
that he will not be fo ftrifrly wedded to every expreflion of
rifiotlcy as to hold it herefie to recede in any thing from him. Nor
is there any queftion to be made, but that if we grant the excel-
lent difpofitioii and pcif^a ord^r of the parts of the Univerfe,
as to local fcituatkon, that then there is no other but the circular
motion, and reft *, for as to the motion by a right line, I fee not
how it can be of ufe for any thing, but to reduce to their natural
conllitution, fome integral bodies that by fome accident were re-

, J feparated from their whole, as we laid above,
^^Lct us now confider the whole Terreftrial Globe, and enquire
the beft we can, whether it, and the other Mundane bodies are to
conferve themfelves in their perfefl: and natural difpofition. It
isneceffary to fay, either that it reftsand keeps perpetually im-
moveable in its place j or elfe that continuing always in its place,
it revolves in irs felf i or that it turneth about a Centre, moving
Arift.^ Ptolomey by the circumfcrence of a circle. Of which accidents, both Ari-
fHiike the Ttrre- g^^/^ and Ftolomcyj and all their followers fay, that it hath ever
z?,^,^^^^^^ and fhall continually keep the firft, that is, a perpetual

^7t is letter to f^y, tcft in the fame placc. Now, why, I pray you, ought they not
thMttheferreftri- , r J J j-jjaj. jts natural afFcftion is to reft immoveable, vtl-

at Globe namr ally CO HdVe .»j i -i

reFieth, than that ther than to make natural unto it the motion * downwards, with
it movethdireniy ^j^j^j^ jtiotion it ncver did or ihall move ? And as to the motion
^rhrword'is, by a right line, they muft grant us that Nature maketh ufe of it
H'^y which the ^^^^5^ j-^^jj p^rts of the Earth, Water, Air, Fire, and every
JicT™^^^^^ other integral Mundane body to their r/We, when any of them
which is quke con- by chance are feparatcd, and fo tranfportcd out of their proper
Ihorsfcnrc!^' ^" p'^^^ *' ^^^^ ^^^^h^ ^^^^ circular motion might not be found
to be more convenient to make this reftitution. In my judg-
ment, this primary pofition anfwers much better, even according
to Ariftotles own method, to all the other confequcnccs , than
to attribute the ftraight motion to be an intrinfick and natural

principle

I A LOG UE.

iim-

lam

tiat

proper
found
judg.
:ording
, than
natural

prinriple of tlic Elements. Which is manifeft , for that if I aske

the Pe

that Coeleftial bodies are

tpateticf^^j it, being or opinion 1
incorruptibe and eternal , he believeth that the Terreftial Globe
is not fo , but corruptible and mortal , fo that there (hall come a
lime , when the Sun and Moon and other Stars , continuing their
beings and operations , the Earth (hall not be found in the
World 5 but (hall with the reft of the Elements be deftroyed
and annihilated, I am certain that he would anfwer me, no:
therefore grencration and corruption is in the parts and not in the Oi€othn
whole 5 and in the parts very fmall and iuperhciai , which are, attributed to the.
as it were , incenfible in comparifon of the whole malTe. And ^^y]^ ^^^^^^^^^^^
becaufe Ariftotle deduceth generation and corruption from the ^ ^
contrariety of ftreight motions , let us remit fuch motions to the
parts , which onely change and decay , and to the whole Globe
and Sphere of the Elements , let us afcribe either the circular mo-
tion , or a perpetual coii(]ftance in its proper place : the only
affeftions apt for perpetuation , and maintaining of perfeft order.
This which is fpokcn of the Earth . may te faid with the fame
leafonof Fire., and S^^^^^^ P^" ^''^ ' which

Elements the r^^ipateticl^s are forced to afcribe for intrinffcal T** ^^^'p^t^tickj

and natural , a motion wherewith they were never yet moved, ^thiP'mlth£%
nor never fliall be , and to call that motion preternatural to them, Elements for
wherewith, if they move at all , they do and ever fliall move. ^hLTLy ncvt
This I fay , becaufe they a(rign to the Air aud Fire the motion were moved, and
upwards , wherewith thofe Elements were never moved , but \ Jtlr^aiwithZM
only fome parts of them , and thofe were fo moved onely in or- they aiwajes are
der to the recovery of their perfeft conftitution , when they were
out of their natural places ^ and on the contrary they call the
circular motion preternatural to them , though they are thereby
inceffantly moved : forgeting, as it feemeth, what Arijietle oft in-
culcateth, that nothing violent can be permanent.

S I M p L- To all thefe we have very pertinent anfwers , which Se^jibu experh
. Ifor this time omit, that we may come to the more particular ^^^'f^^A^,^^^
reafons , and fenfible experiments , which ought in conclufion to ArgJmmH""^'^^
beoppofed, as Arijiotlefmh well, to whatever humane reafon
can prefect us with.

Sagr. What hath beenfpoken hitherto, ferves to clear up
unto us which of the two general difcourfes carrieth with it moft
of probability, 1 mean that of y^ri/ia^/e , which ^ould perfwade
^s>that the fublunary bodies are by nature gen^rable, and corru-
ptible, i^c. and therefore moft different from the eifence of Coe-
leftial bodies , which are impafTible , ingenerable, incorruptible,
drawn from the diverfity of fimple motions j or elfe this of
Sahiatus^ who fuppofing the integral parts of the World to be
^fpoled in ^ perfcft conftitution , excludes by ^neceffary confe-

E quence

2^ G. GALiLJEUSyhis Sylleme.

quence the right or ftraight motion of limple natural bodies, as
being of no ufe in nature, and efteems the Earth it fclf aUo to
be one of the Cctleftial bodies adorn d with all the prerogatives
that agiec with them j which laft difcourfe is hitherto much
move likely, in my judgment, than that other. Therefore re-
folve, Simflictus-, to produce all the particular reafons, experi-
ments and obfcrvations, as well Natural as Aftronomical, that
may ferve to peifwadc us that the Earth differcth from the Coc-
leftial bodies, is immoveable, and fituated in the Centre of the
World, and what ever elfe excludes its moving like to the Planets,
as Jupiter or the Mooji^ And Sal^iatns will be plealed to

be fo civil as to anfwer to them one by one.

S I M P L. See here for a begining, two moft convincing Argu-
ments to dcmonftrate the Earth to be moft different from the
Coeleftial bodies. Firft, the bodies that are gcnerable, corru-
ptible, alterable, C^f. are quite different from thole that are in-
generable, incorruptible, unalterable, &*c. But the Earth is ge-
nerable, corruptible, alterable^, e^r. and the Coeleftial bodies in-
generable, iflcorruptible, unalterable, &^c. Therefore the Earth
IS quite diflEerent from the Coeleftial bodie?.

S A G R. By your firft Argument you fpread the Table with the
fame Viands, which but juft now with much adoe were voided.

SiMPL. tl^^^ ^ ^^^^ ^'^"8 ^i^li you,

and then tell me if this be not different from what you had be-
fore . I" the former, the Minor was proved a prior i^Sc now you fee
it proved a poftertori : Judg then if it be the fame. I prove the
Mi/^^r^thereforc (the Major being moft manifeft J by fenfible ex-
perience, which fhews us that in the Earth there are made conti-
nual generations, corruptions, alterations, c>c. which neither our
ien£cs, nor the traditions or memories of our Anccftors, ever faw
an inftance of in Heaven ^ therefore Heaven is unalterable,
ffeaven imtnuU' Earth alterable, ^r. and therefore different from Hea-

lt)rZtytZ ven. I take my fecond Argument from a principal and effential
ration feen in it. accident , and it is this. That body which is by its nature ob-
Bodiet naturally fcute and deprived of light , Is divers from the luminous and fhi-
lucid, are df event . , ^j^^ £^j.th is obfcute and void of light , and the

from thoje tvhtch uuun-*^ i i j. i J r 11 r r i i? ^

are hj nature ob- Coelcftial bodics fplcndid , and tuU ot light j Lrgo-, &c. Anfwer
to thefe Arguments firft , that we may not heap up too many,
and then 1 will alledge others.

S ALV- As to the firft-, the ftreffc whereof you lay upon ex-
perience, I defire that you would a little more diftinftly produce
me the alteration which you fee made in the Earth, and not in
Heaven ■, upon which you call the Earth alterable, and the Hea-
vens not fo.

S I M P L- I in the Earth, plants and animals continually ge-
nerating

Dl A LOG UE.

Lies m-
larth

the

: conti-
her our
.^er faw

m Hea-
rlTential
MC ob-

and the
Anfwer
> many,

pon ex-
5roduce
1 not in
lie Hea-

lerating

nerating and decaying h winds, rains, tcmpefts, ftorms anfing ; and
in a word, the afpea of the Earth to be perpetually metamorpho-
fing none of which mutations arc to be difcern d in the Cceleftial
bodies j the conftitution and figuration of which is moft punSu-
ally conformable to that they ever were time out of mind^ without
the generation of any thing that is new , or corruption of any thing
that was old.

S \ L But if you content your felf with thefe vifible , or to
fay better , feen experiments , you muft confequently account
Chinorrgtnd America Coeleftial bodies, for doubtleffe you never
beheld in them thefe alterations which you fee here in Italy , and
that therefore according to your apprehenfion they are inal-
terable-

Sim PL. Though I never did fee thefe alterations fenfibly in

thofe pUcQs , the relations of them are not to be queftioned i

befides that , cum eadem ft ratio tot ins -i ^ fartium y thofe

Countreys being a part of the Earth 5 as well as ours , they

muft of neceflity be alterable as thefe are.

S a l v. And why hav^ >-7 ' TTr"' ^Tl '
other mens xelations , exammcd and obterved thofe altcrationi

with your own eyes ?

S I MPL- Becaufe thofe places , befides that they are not ex-
pofed to our eyes , are fo remote , that our fight cannot reach
to comprehend therein fuch like mutations.

S A L V, See now, how you have unawares difcovered the falla-
cy of your Argument , for, if you fay that the alterations that
are feen on the Earth neet at hand, cannot, by reafon of the too
great diftance,be feen in America , much lelTe can you fee them
in the Moon , which is fo many hundred times more remote :
And if you believe the alterations in Mexico upon the report of
thofe that come from thence , what intelligence have you from
the Moon , to affure you that there is no fuch alterations in it >
Therefore, from your not feeing any alterations in Heaven,
whereas, if there were any fuch , you could not fee them by rea-
fon of their too great diftance , and from your not having intel-
ligence thereof , in regard that it cannot be had , you ought not
to argue , that there arc no fuch alterations , howbeit,from the
feeing and obferving of them on Earth , you well argue that
therein fuch there arc. • • i r

Simp i.. I will (hew 10 great mutations tb^t have befaln on
^l^c Earth , that if any fuch had happened in the Moon , they
miglu very well have been obferved here below. We find in
very ancient records , that heretofore at the Streights of Gibraltar,
the two gicat Mountains Abila, and Calpen, were continued td- ./ Ai.-,
getherby certaia other Icffe Mountains , which there gave check

E 2

G. G A L 1 L u bis SyfJeme.

to the Oceaii; : but thofe Hills , being by fome caufc or other fe-
paratcd, and a way being opened for the Sea to break irt^it made
fuch an inundation) that it gave occafion to the calling of it fince
the Midland Sea : the greatnefs whereof confidered, and the di-
vers afpeSs the furfaces of the Water and Earth then made 5 had it
beeti beheld afar off, there is no doubt but fo great a change
might have been difcerned by one that was tlien in the Moon ;
as alfo to us inhabitants of the Earth, the like alterations would
be perceived in the Moon j but we find not in antiquity, that
ver there was fuch a thipg feen h therefore We have n6f Caufe td
fay, that any of the Coeleftial bodies are alterable,

Salv- That fo great alterations havehapned in the^IVtdon, I
dare not fay, but for all that, I am not yet cerrain but that fuch
changes might occurs and becaufe fuch a mutation could onely
Teprefent4into us fome kind of variation between the m6re clear,
and more obfcure parts of the Moon, I know not whether we
have had Oil Earth obfervant SelenograjJiets, who have for any
confiderable number of years, inftruSed us with fo exaft Seleno-
graphy, as that we ftould confidently coi^elude, that there hath
no fuch change hapned in the face of the Moon i of the figura-
tion of which I find no more particular defcription, than the fay-
ing of fome, that it reprefents an humarie face h of others, that
it is like the mnzU of a Lyon j and of others, that it is Cain with
a bundle of thorns on his back : therefore, to fay Heaven is un-
alteriiblc^becauferhat in the Moon, or other Coeleftial bodies, no
fuch alterations are feen, as difcover themfelves on Earth, is a bad
illatidb, and concludeth nothing.

S A G R- And there is another odd kind of fcruple in this Argu-
ment of Simpltcit0^ running in nfiy mind, which I would gladly
have anfwered j therefore I demand of him, whether the Earth
before thcMeditcrranian inundation was generable and corrupti-
ble, or elfe began then fo to be ?

Sim PL* It wasdoubtlefs generable and corruptible alfo be-
fore that time ; but that was fo vaft a mutation , that it might
have been obferved as far as the Moon.

Sa gR. Go to^ if the Earth was generable and corruptible
before that Inundation , why may not the Moon be fo like-
wife without fuch a change > Or why (hould that be neceffary
in the Moon, which importeth nothing on Earth >

Salv- It isaflirewd queftion : ButI am doubtfull that Sim^
flicim a Httle altercth the Text of Arijiotle^ and the other Peri-
pateticl{s^ who fay, they hold the Heavens unalterable, for that
they fee therein no one ftar generate or corrupt, which is proba-
bly a lefs part of Heaven, than a City is of the Earth , and yet
innumerable of thefe have been deftroyed, fo as that no mark of
them hath remainU S a G R-

^Argii-

gladly
Earth

rrupn-

Dialogue!. 57

^ A GR' r verily believed ocherwife, and conceited thatiyi;^-
plhcins d'lffemhhd this expofition of the Text^ that he might not
charge his Matter and Confeaators, with a notion more abiurd
than the foniier. And what a folly it is to' fky the Coclcftial
part is unalterable, becaufe noftars^ do generate or corrupt there-
in? What then? hath aiiy one feen a Terreftrial Globe corrupt^and
another regenerate in its place? And yet is it not on aft hands
granted by Fhilofophers, that there are very few ftars i^Plfeav^A
lefe than the Earth, but very many that aipe^much bigger^? So
that for a ftar in Heaven to corrupt, would be fiolefs. than if. the luJoJt fi!r tl
whole Terreftrial Globe fbould be deftroy'd. There fore^ if for <^o^ri*pt , than for
the true proof of generation and corruption in^ the Univerfi?, it be ^alcioh^^^'^''
neceffary that i'o vaft bodies as a ftar, muft corrupt and regene-
rate, you may fatisfie your felf and ceafe your opinion *, for I
affare you, that you fliall never fee the Terreftrial Glote- or any
other integral body oiF the World, to corrupt ot decay fo, tfiat
having been beheld by us for fo many years paft, they (hould fo
diffolve, as not to leave any foot^^'^i^s of ck<^

S/vLv. But to oiv^ ^^fficim yet fuHer f^ri^aak>«, ar^d to
reclaim him, i^* f^^I^' f^^"^ his error 5 I affirm, that we have ?A
ottr age new accidents and obfervations, andfuch, that I queftion chL^fht^Thn
not in the leaft, but if Arijiotle were now alive, they would naakd duil fel IheTo-
him change his opinion 5 which riiay be eafily colleflted from the '^'^^^'^^f^^rage.
very manner of his difcourfing For -when he writeth th^it he e-
fteemeth the Heavens inalterable,' '&c. becaufe no new thing was
feen to be begot therein, or any old to be diflblved, he feems im-
plicitely to hmt unto us, that when ce (hould fee any fuch acci-
dent, he would hold the contrary , and confront, as indeed it is
meet, fenfible experiments to natural reafoii : for had he not
made any reckoning of the fenfes, he would not then from the
not feeing of any fenfible mutation, have argued immutability.

SiMPL- Arijiotle deduceth his principal Argument a friori^
Ihewing the neccflity of the inalterability of Heaven by natural,
manifeft and clear principles j and then ftabliflieth the fame a po^
fieriori, by fenfe, and the traditions of the antients.

Salv. This you fpeak of is the Method he hath obferved in
delivering his Doarine , buf I do not bethink it yet to be that
wherewith he invented it h for I do believe for certain , that he
firft procured by help of the fenfes , fuch experiments and obfer-
Nations as he couldjto afTure him as much as it was po{rible,of the The certainty of
c^ncluaon , and that he afterwards fought out the means how to ^^' cond^.^^nhei'
uemonltrate it : For this is the ufual courfe in demonftrative Scien- method to find the
ces , and the reafon thereof is , becaufe when the conclufion is dcmo^sirathH.
true, by help of refolutive Method, one may hit upon fome pro-
pofition before dcmonftrated , or come to fome principle known

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

G. G A L I L * u s, hit Syfieme:

butiftheconclufionbefalfe, a man may proceed i« i«-
fjr fe , ^^^^^eetwithany truth already known butve-

^" He fl«ll meet with fomc impoffibiUty or manifeft abfurdi-

P,.H,,ons.j../,^; Nor need you queftion but that ^'^'^Jf --V^-g
« H«4«J /.r i; ri ihe demonftration for which he offered the Hecar
.G«v./i«- fore he found . ,j..r„uare of the fide lubtendin^

,n..ilr.M,ch tomb , had been certain, that the iquare oi inc i „
'"f""'^ the right angle in a re6tangle triangle , was equal to the Iqu^re ol
therigncangi .^nd the certainty of the conclufion condu-

'^rnt'Xl to\he iTve^^^^^^ ot\he demonftration, un,
^ (vTndi^e me Ilwayes to mean in demonftrative Science.. Bu^
what et waT heiJhodof A.fiotle and whether his arguingi
rprrdedfenfe a poftermi , or the contrary iit fufficeth that
K 7 ^T^fttrpreferrith (as hath been oft laid) fenfible- ex-
^»Ss b£ea&^^ befides, as to the\rugments i
E Aeir force hath been aheady examined. Now returning
Lmv Purpofcd matter, Ifay, that the things in our times dif^
covered in the Heavcns,are, and have been fuch , that they may
oive abfolute fatisfaaion to all Phi ofophers , forafmuch as m
S • 1 and in the univcrfalcxpanfion of Heaven,

t fi« Sd are continually, feen juS fuch accidents a.
t^ciHene ^aonsand corrMptions , being that excellent A-
we g uc^^^^A inanv Comets generated and diflTolved

ftronomcrs have obfervc^^^^^^ ^J^^^ ^^^^^^ ^^^^^^^^^

in parts hig ^^^^ ^^^^ ^ without contradiaion much higher
" *,?4e Planets i and in the face of the Sun it felf , by help
Zl'^'^ th. -^^^^^^^ certain denfe and obfcurefubftances, in fem.

%"dX'b>f'c. j^j^^^^ like to the foggs »bout the Earth, are feen to be
produced and dilTolved •, and many of thefe are fo vaft, that
thev far exceed not only the Mediterranian Streight , but all

s.ur S}.s Jjlica^nd Afia^Ko. Now if ^njio./e had feen theft things,

g;;Z»-«A-XtthinkyouhewouIdhavefaid, and done ?

A AflrKk. ^''f 77 \ k„ow not what Arifiotle would have done or faid,
that was the great Mafter of all the Sciences , but yet I ktiow in
part what his Sedators do and fay , and ought to do and fay
unleffethey would deprive themfelvesof their guide leader, and
unieue tncy As to the Comets, are not thofe Modern

Snl^ w^^^^^^ them Ccleftial, convinced by

Altronomc. , ^ overcome with their own weapons, I

concluding It the laft in favour of ArM , that they are all
Elementary > And this being overthrown, which was as u were
their foundation, have thefe Novellifts any thing more where- J
with to maintain their a{fcrtion ? >S
Salv. Hold a little, apod Simphaus , this modern Author, ^
what faith heto the new Stars , Anno 1 5 /a, and 1 604 , and to 1

I A L O G U E

it-
it ve-

P>e>

leca-

tot

. But
Liingi
h that
Ic* ex-
^rvts i
ping

Even,
:nts as
:nt A-
ffolved
J Stars,
higher
•y help
m fern-
I to be
, that
but all

iiungs,
^faid,
5W in
tid fay,
ier, and
iodern
d by
pons, I
^tryed,
ire all
pwere
■fhere-

Kuthor,
and to
the

the Solar fpots ? for as to the Comets , 1 for my own particular
little care to make them generated under or above the Moonj
nor did I ever put much ftreffe on the loquacity of Tycho j nor
am I hard to believe that their matter is Elementary , and that
they may elevate (fubhmate) themfelves at their pleafure, with-
out meeting with any obftacle from the impenetrabiUty of the
Penpatetul^ Heaven 5 which I hold to be far more thin, yielding,
and fubtil than our Air j and as to the calculations of the Pa-
rallaxes, -firft, the uncertainty whether Comets are fub)e£i: to
fuch accidents, and next , the inconftancy of the obfervations,
upon which the computations are made, make me equally fuf-
peft both thofe opinions : and the rather , for that I fee him Anti-Tycho me-
you call Ami'Tychoy fome times ft retch to his purpofe , or clfe
rcjeft thofe obfervadons which interfere with his defiffti. ol,f.rv«.o.< his

oiMP.L. As to the new Stars ^ Anti-Tycho extricates mmieli
^My. in three or four words , faying, That thofe mo-
dern new Stars are no certain parts of the CoclcftiaJ bodies , and
that the adverfaries , if they will prove alteration and genera-
tion in thofe iuperior l^^-^"' muft ihcw f^^^ ««utAtions that
have been made «^ the Stars defcribed fo many ages paft, of
which F^r« is no doubt but that they be Coelcftial bodies ^
which they c^in never be able to do : Next, as to thofe mat-
ters which fome affirm, to generate and diffipate in the face of
the Sun, he makes no mention thereof ^ wherefore 1 conclude,
that he believed them fiftious , or the illufions of the Tube, or
at raoft, fome petty efFefo caufed by the Air, and in brief, any
thing rather than matters Coeleftial.

S ALv. But yow^ Simplicim-i what anfwer could you give to
the oppofition of thefe importunate fpots which arc ftarted up
to difturb the Heavens, and more than that, the Ferzpatetick^
Philofophy ? It cannot be but that you, who are fo refolute a
Champion of it , have found fome reply or folution for the
fame, of whi^li you ought not to deprive us.

SiMPL. I have heard fundry opinions about this particular.
One faith ; " They are Stars which in their proper Orbs, like as
yenus and Mern/rj^, revolve about the Sun, and in paffing un- touchll^CsoZ
der it, rcprefent themfelves to us obfcure ; and for that they
''are many, tbey oft happen to aggregate their parts together,
'^^and afterwards feperate again. Others believe them to be
''aerial impreffions h others, the illufions of the chryftals j and o-
thcrs, other things : But 1 incline to think, yea am verily per-
'iw^ded, That they are an apgrcgate af many feveral opacous

c] A' ' " """-^ aggregate many leverai opacous

^1 bodies, as it were cafually concurrent among themfelves. And
therefore we often fee , that in one of thofe fpots one may
number ten or more fuch fniall bodies . which are of irregu-

"lar

4© G. Galil^us, hisSyflcme.

^' lar figures , and feem to us like flakes of fnow , or flocks of
" wooll, or moaths flying : they vary fite amongfl: themfelves,
and one while fever, another while meet, and mofl of all be-
"neath the Sun, about which, as about their Centre, they con-
t'tinually move. But yet, muft we not therefore grant, that
they are generated or dilfolved , but that atfometimes they are
hid behind the body of the Sun , and at other times , though
remote from it, yet are they not feen for the vicinity of the
immeafurable light of the Sun j in regard that in the cccentrick
Orb of the Sun , there is conflituted, as it were, an Onion, corn-
ed pofed of many folds one within another , each of which, being
* The Original " ftudded with certain fmall fpots , doth move ^ and albeit their
h\ih\temfeflMa ft cc motion at firfl: feemeth inconfl:ant and irregular , yet neverthe-

tnmve] which the , rr_ r<^\A it lalV . to be obfprvpd fKif rlip vprv fame fonfc

^'"rr-'-r luUHUH At iii*^ tj ^ J

] which the np itisfaidatlaft, to be obferved that the very fame fpots,
on , ( miftaking cc before , do withm a aeterminate time return agam. This

.1 ^ . ^l.^ Ct't-^n*^ '\r\\\\Tf>r V«»M^ (-t^ttt^ ^ .

rfwp^/?4M,aword to me the fittefl: anfwer that hath been found to afligne

remfeftallS ^^""Z a rcafon of tjiat fame appearance , and withal to maintain the
dercth [ incotrupt ability and ingenerabihty of the Heavens ^ and if this
iTgXhlviol"^^ there wants not more elevated wits , which will

tranfportmeut , as other, tnore convincing.

a'shf'""''^" Salv- If this of which we difpute , were feme point of Law,
/„ nati^Mi Sci' or other part of the Studies called Humanity , wherein there is
e^ces, the art of ^^j^j^^^ ^^^^i^ nor falOiood , if wc will give fufficient credit to
forty " the acutenefle of the wit, readinefleof anfwers, and the gene-
ral praftice of Writers , then he who moft aboundeth in thefe,
makes his reafon more probable and plaufible ^ but in Nat^ural
Sciences , the cone lufions of which are true and neceflary , and
wherewith the judgment of men hath nothing to do , one is to
be more cautious how he goeth about to maintain anything that
is falfe 5 for a man but of an ordinary wit , if it be his good for-
tune to be of the right fide , may lay a thoufand Demofihcnes and
a thoufand Ariftotles at his feet. Therefore rejeft thofe hopes
and conceits, wherewith you flatter your felf, tbat there can be
any men fo much more learned , read , and verfed in Authors,
than we ? that in defpite of nature , they ftiould be able to
make that become true , which is falfe. And feeing that of all
the opinions that have been hitherto alledged touching the ef-
fence of thefe Solar fpots , this inftanced In by you , is in your
judgment the truefl: , it followeth (if this be fo) that all the reft
are falfe h and to deliver you from this alfo , which doubtlefle is a
moft falfe Chimcera , over-pafling infinite other improbabihties
that are therein , I (hall propofe againfl: it onely two experiments-,
j4n AriumeM jg ^ that many of thofe fpots arc feen to arife in the midft of
fZethThl^ZiIr the Solar ring , and many likewife to diflblve and vanifli at a great
fpots to ^^wr'*^* difl;ance from the circumference of the Sun, aneceffary Argu-

.^nd dijfolve, jj^^j^j.

I A L O G U E

cks of
selves,
11 be-
r con-

that
ey are
hough
)f the
'ntrick
, corn-
being
it their
rerthe-
fpots,

This
affigne
un the
if this
|will

f Law,

;here is
edit to
- gene-
i thefe,
^at^ural
y, and
[le is to
ig that
ad for-
nes and

^pes
I be
ithdrs ,
Mc to
m all
peef-
in your
the reft
■Teisa
roilities
itnents*,
l^of
Igreat
{ Argu-
ment

and diffolve ^ for if without gc

A conclufivt de»

ment that they generate

or corrrupting, they fliould appear there by onely local motion,
thev would all be feen to enter, and pals out by the extreme cir-
cumference. The other oblervatron to inch as are not lituate m ^j„jirmoH, that
the lowcft degree ofienorancc in PerfpeSive, by the mutation t^^i/^^^^ ^rjc.^tir-
of the appearing figures, and by the apparent mutations ot tlie ^^^^^^
velocity of motion is neceffarily concluding , that the fpots are
contiguous to the body of the Sun, and that touching its fupcrfi-
cies, thsy move either with it or upon it, and that they in na wife
m6vc in circles remote from the fame. The motion proves The motion of the

which towards the circumference of the Solar Circle ,
appeareth very flow, and towards the midft, more fwift ^ the the s»» apfsars
gures of the fpots confirmeth it, which towards the circumference
appear exceeding narrow in comparifon of that which they feem ff^ts avfears nar-
to be in the parts nearer the middle i and this becaufe in the ro^ towards the
midft they are feen in their fulllufter, and as they truly be, ana thesnnsd:ikvi^,^,
towards the circumference by reafon of the convexity of the glo* n?^;.
bous fuperficies, they feem more compreff'd : And both thefe
diminutions of figure and it»--— ^^^^^ ^"ow how to obfcrve
and calculate thcmc^aaiy, prccifely anfwet to that which ftould
appear, the fpots being contiguous to the Sun, and difter irrecon-
cilcably from a motion in circles remote, though but for fmal
intervalls from the body of the Sun--, as hath been difFufcly de- ^^^^^^^^^.^^^^^
monftrated by our Friepd, in his Letters about the Solar fpots,

fr/Wi as alfochat

to Marcus Velfttm. ^ It may'W gathered from the fame muta- ^^^f^'^f'^'^^^^^
tion of figure^ that none of 'them are ftars, or other bodies of modcftiy*
fpherical figure i for that amonaft all figures the fphere never conceais himfeif

f .0 • ^, r^JU-T T throughout theic

appeareth comprelTcd, nor can ever be reprdented but onely per-* j;)iayogues.
f^ly round 3 and thus in cafe any patticular fpot were a round
body, as all the ftiUrs aw held to be, the faid roundnrfa would as
wfell appear in the midft bf the Solar ring, as when the fpot is near
the extreine : whercas) itsfo great compreflion, and fliev^ing its
felffofm^ill toward^ dke^sxtreme^ and contrariwife, fpatious and
ki'ge towairdsthe itiiddle, a (Tare th us , that thefe fpots are flat SoUrfiots
plates of fmall thicknefo or depths in comparifon of their length are Lt "fphencai,
and breadth; Laftly, whereas you fay that the fpots after their i'^'jtjat itke thin
deter mmate periods ar^ obferved t<» return to their former alpeft,
believe it not, SimpUcins^ for he that told you fo, will deceive
you i and that 1 fpeak the truth, you may obferve them to be hid
in the face of the Sun far from the circumference ^ nor hath your
^bfervator told you a word of that compretf^on, which necefTa-
rily ^rgucth them to be contiguous to the Sun. That which he
tells you of the return of the faid fpots, is nothing elfe but what
is read in the forementioned Letters, namely, that fome of them
may fometimes fo happen that are of fo long a duration? that

F they

42 G. G A L I L i?: u s, his Syjleme.

they cannot be diffipated by one folc converfion about the Sun,
which is accompliflied in lefs than a moncth.

Sim PL- h for my part, have not made either fo long, or fo
exaft obfervations, as to enable me to boaft my felf Mafter of the
Quod eii of this matter : but I will more accurately confidcr the
fame, and make tryal my felf for my own fatisfaSion, whether I
can reconcile that which experience (hews us, with that which
Arijiotle teachethus , for it's a certain Maxim, that two Truths
cannot be contrary to one another.

Salv« If you would reconcile that which fenfe flieweth you,
OnecAnm (faith ^^^^ the foUdcr Doftrines of Arijlothy you will find no great dif-
Aiiftocle) i?^4iLficulty in the undertakings and that fo it is, doth not ArifiotU
vefft^reafi^^^ ^h^t onc cannot treat confidently of the things of Heaven,
'it$\reatdtfiance, by rcafon of their great remotcnefs ?

S I M P L. He exprefly faith fo.
hu({oi\<tpTifers S AL V- And doth he not likewife affirm, that we ought to pre-
fenfe Before ratio- jfer that which fcufc demouftrates, before all Arguments, though
etnatton. appearance never fo well grounded ? and faith he not this

• without the leaft doubt or hacfitation ?

SiMPL. He doth fo. ^
S AxV* Why then, the fccond of thefe propofitions, which ar^
Jtsadottrinemote^^^^ doftrfnc of AriftotU:, that faiths that fenfe is to take
s^eeing Zith A- place of Logick, is a dodrine much more folid and undoubted,
nftotlc. to fay the ^^^^ ^\^^t Other which holdeth the Hea^ns to be unalterable • and
^^"Xrfrr therefore you fliall argue more jAfiotdicaUy, faying, the Hea-
rphich affirms yens irc alterable, for that fo my fenfe telleth me, than if you
them inalterable, ^^^j j f^y^ ^hc Hcavcns are u alterable, for that Logick fo perfwa-
AW f AriBotle. Furthermore, we may difcourfe of Cacleftial mat-
Tdefcope V- ^^^^ ^^^^ ^'^^f' ^ri/i(^//e ; becaufe, he confeffing the know-

courfe Better efcoe- Icdg thereof to be difficult to him, by reafon of their remotcnefs
ifJnLCTm' ^'""^ ^^^^^'^ ^^^''^^y acknowledgeth, that one to whom
felf. the fenfes can better rcprefent the fame, may philofophatc upon

them with more certainty. Now we by help of the Telefcope,
are brought thirty or forty times nearer to the Heavens, than ever
Arijiotle came j fo that we may difcover in them an hundred
things, which he could not fee, and amongft the rejft, thefe fpots
in the Sun, which were to him abfolutcly invifible i therefore
wc may difcourfe of the Heavens and Sun, with more certainty
than Ariftolte.

S A G R. 1 fee into the heart of Stmplucius^ and know that he is
much moved at the ftrength of thefe fo convincing Arguments j
but on the other fide, when he confidereth the great authority
which Arijiotle hath won with all men, and remembreth the great
number of famous Interpreters, which have made it their bufinefs
to explain his fenfe ^ and fccth other Sciences^ fo ncceffary and

profitable

I A L O G U E.

Sun,

you,
tSLt dif-
IriflotU
caveuj

I pre-
:)ugh
this

iich are
to take
aubted,
and
^Hea-
if you
perfwa-
ial mat-
; know-
lotenefs
whom
c upon
efcope,
in ever
iUndred
fe fpots
ereforc
tainty

he is
nents ;
thority
e great
ufinefs
ry and
"table

profitable to the publick, to build a great part of their efteem

puzzled and

and

L the credit of

ireputati ^

perplexed : and methinks I hear him fay, To whom then fliould neD^cUmathn
we repair for the decifion of our controverfies, if Jnpotle were ^/SimpHcius.
removed from the chair? What other Author ftiould we follow
in the Schools, Academies and Studies ? What Philofopher hath
writ all the parts of Natural Philofophy, and that fo methodically
without omitting fo much as one finglc conclufion > Shall we then
overthrow that Fabrick under which fo many pafTengers find
flielter ? Shall we deftroy that Jfylum, that Prytaneum, where-
in lo many Students meet with commodious harbour , where
without expoling themfelves to the injuries of the air, with the
oneJy turning over of a few leaves, one may learn all the fe-
crets of. Nature? Shall we difmantle that fort in which we are
late trom all hoftile aflaults ? But I pitie him no more than I do
that Gentleman who with great expence of time and treafurcj
and the help of many hundred artifts , e reds a very fumptu-
ous Pallace, and afterwards beholds it ready to fall, byreafoa
ot the bad foundation : ^^'"B extrc.«^jy ^^^aiing to fee
the Walls ilript which are adorned with fo many beautiful!
Piaurcs i or to fulFer the columns to fall, that uphold the {late-
ly Galleries ; or the gilded roofs ^ chimney-pieces , the freizcs
the cornilhes of marble, with fo much coft erefied, to be rui!
ned 3 gocth about with girders, props, (hoars, butteraifes, to pre*,
vent their fubverfion. t

S ALv. But alafs, Simplicius as yet fears no fuch fall, and
1 would undertake to fecure him from that mifchief at a far
leis charge. There is no danger that fo great a multitude o£ "P^ipdtctick.Phi-
w i ^"""^ wiJ'e Philofophers, Oiould fufFer themfelves to be I'^^f^
tietlor d by one or two, who make a little bluftering i nay,
they will rather , without ever turning the points of their pens
^gainft tliem , by their filence oncly render them the objea of
univcrfal fcorn and contempt. It is a fond conceit for any one
to think to introduce new Philofophy, by reproving this or that
Author : it will be firft necefTary to new-mold the brains of
men, and make them apt to diftinguift truth from falfliood. a
tning which onely God can do. But from one difcourfe to another
^hither are we ftray d } your memory mull help to guide me into
^he way again.

^iMPL. I remember very well where we left. We were

^P^n the anfwcr of Anti-Tycho y to the objeQions againft the

o?^r^^'''^^ of the Heavens, among which you inferted this

i !^ A^^^^ ^^^^^ ' ^ believe you

ntended to examine his anfwer to the inllance of the New
^tars. , ,

F 2

44 G. G A L 1 L u S;, bis Sjflme.

Sa-LV- Now 1 remember the reft, and to proceed, Methinks
there are fome things in the anfwcr of Anti-Tycho^ worthy of
reprehenfion. Andfirft, if the two New Stars, which he can do
no lefs than place in the uppermoft parts of the Heavens , and
which' were bf a long duration, but finally vanifhed, give him no
dbftruftion in maintaining the inalterability of Heaven, in- that
they were not certain parts thereof, nor mutations made in the
antient Stars, why doth he fet himfelf fo vigoroufly and earneftly
dgainft the Comets, to banifti them by all ways from the Coele^
ftial Regions? Was it not enough that he could fay of them
the fame which he f poke of the New fiars ? to wit> that in re-
gard they were no certain parts of Heaven, nor mutations made
in any of the Stars , they could no wife prejudice either Heaven,
or the Doftrirte of AfiftotU > Secondly, I am not very wdl fatis-
ficd of his meaning when he faith that the alterations that fiiould
be granted to be made in the 5 tars , would be deftruftive to the
prerogative of Heaven h namely , its incorruptibility, d^c. and
this 5 becaufe the Stars are Coeleftial fubftances , as is manifeft
by the confent of every one*, and yet is nothing troubled that
•Excra Stellas. the fame altera tioi\s fliould be made * without the Stars in the reft
of the Coeleftial expanfion. Doth he think that Heaven is no
Coeleftial fubftanc^> I, for my part, did believe that the Stars
were called Coeleftial bodies , by reafon that they were in Hea-
ven? or fcJt that they were made of the fubftance of Heaven ;
and yet I thought that Heaven was more Coeleftial than they, jn
like fort , as nothing can be faid to be more Terreftrial, or more
fiery than the Earth or Fire themfclves. And again, in that he ne-
ver made any mention of the Solar fpots , which have been evi-
dently demonftrated to be produced , and diffolved , and to be
neer the Sun , and to turn either with, or about the fame , I have
reafon to think that this Author probably did write more for others
pleafure, than for his own fatisfadion h and this I affirm , foraf-
much as lie having ftewn himfelf to be skilful in the Mathcma-
ticks , it is impoffible but that he fhould have been convinced by
Demanftration^ , that thofe fubftances are of neceffity contigu-
ous with the body of the Sun , and are fo great generations and
corruptions , that none comparable to them, ever happen in the
5^ith : And if fuch, fomany, and fo frequent be made in the
very Globe of the Sun , which may with reafon be held one of the
nobleft parts of Heaven , what fliould make us think that others
may not happen in the other Orbs ?
CenerAbiiny arJ Sagr. I cannot without great admiration , nay more, deni-
""^Zur^rfeai'^ ^^^^^ undcrftandiiig, hear it to be attributed to natural bodies,
/« the Worlds ho' for a great honour and perfeftion that they are impaflible , im-
t%^^LttuT' inalterable, ^c. And on the contrary , to bear it to

Impacible. bc

I A L O G U E I.

eaven.

eni-

iies.

mirablc

be eftcemed a great iinperfeaion to be alterable, gencrable, mu-
. it is my opinion that the Earth is very noble and ad-
by rcafon of fo many and fo different alterations, mu-
rations, generations , which are inceffantly made therein
and if without being fabjeft to any alteration , it had been all
one vaft heap of fand , or a maffe of Jafp^r , or that in the time
ox the Deluge , the waters freezing which covered it, it had
t^ontinuedan immenfe Globe of Chriftal, wherein notbitig had
ever grown , altered , or changed , I fliould have efteemed it a
lump of no benefit to the World, full of idlencffe , and in a
word fuperfluous , and as if it had* never been in nature and
ihQuld make the fame difference in it, as between a living and
dead creature : The hke Hay of the Moof^ jHpitcr, and the
other Globes of the World. But the more I' dive into the con-
fideration of the vanity of popular difcourfes-,: the more empty
and fimple I find them. And what greater folly can there be
imagined, than to call Jems, Silver and Gold pretious s and Earth
aiiddirt vile> Fordo not thefe perfons con^der , that if there
would be as great a fca-^^r Eartl» , a« jewels and

pretious metals. «=»^re would be no Prince, but would gladly give
a heap o£ Diamonds and Rubies , and many Wedges of Gold
to purchafe onely fo much Earth arffliould fuffice to plant a Geffe-
mmein a little pot, or tafet theueirt ^ Qhina Orange^ that he m#gKt
fee it fproHty grow up , and bring forth fo goodly leaves , fo odi-
nferous flowers , and fo delicate fruit ? It is therefore fcarcity and
plenty that make things efteemed and cohtemoed by the vulgar j
who will fay that fame is a moft beautiful Diamond , for that it
^lembleth a clcer water , and yet will not part with it for ten
fun of water: Thefc men that fo extol incorruptibility, inalte-
rability, &*c. fpeak thus 1 believe out of the great defire they
have to live long, and for fear of death ; not confidering, that
it men had been immortal , they fliould have had nothing to do
w the World. Thefe deferve to meet with a Mednfas head ,
that would transform them into Statues o( Dintond and JaJ}>er,
that fo they might become more perfeft than they are.

S A L V. And it may be fuch a Metamorphafis would not be al-
together unprofitable to them j for I am of opinion that it is bet-
ter not to difcourfe at all , than to argue erronioufly-

S iM p L. There is not the leaft queftion to be made , but that
Earth is much more perfefl:, being as it is alterable, mutable,
than if it had been a maffe of ftone 5 yea although it were
^ne entire Diamond, moft hard and impaflile. But look how much
lele qualifications cnoble the Earth , they render the Heavenly
odies again on the other fide fo much the more imperfeft , in
Which, fuch conditions would be fuperfluous , in regard that the

Coele^

Tie Earth vsry
noble J bj reason of
the many mutati-
ons made therein*

The Strth Mfffro-
fitable and f^ll of
idlenejje^ tts altc
rations taken awAj

The Earth mort
noble than Gold
and Jewels,

Scarcity and plen^
tj enhanfeand de^
y^fe the price of
things,

^"corruptibility e»
fleemedbythevtil-
£ar out of their
fear of doAth,

The difparagers of
corruptibility dc
ferveto be turned
***to Status's, .

The Cotlr.flial be-
dies deftgned to
ferve the Earthy
need no more bt^t
motion and lights

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

G. G A L I L ^ us, his Syfieme.

Gttlefiial bodies , namely, the S'un, Moon, and the other Stars,
which arc ordained for no other ufe but to ferve the Earth, need
no other qualities for attaining of that end, fave onely thofe of
light and motion. , , , , i

S AGR. How ? Will you affirm that nature hath produced and
defigned fo many vaft perfefl and noble Coeleftial bodies , impaf-
fiblc, immortal, and divine , to no other ufe but to ferve the paf-
fible, frail, and mortal Earth > to ferve that which you call the
dro£fe of the World , and fink of all uncleanneffe ? To what
purpofe were the Gocleftial bodies made immortal, &c. to ferve a
frail, &*c. Take away this fiibfervicncy to the Earth , and the in-
numerable multitude of Coeleftial bodies become wholly unufe-
CtUnui bodies ^ fuperfluous , fincc they neither have nor can have any
TaLZc mutual operation betwixt themfelves i becaufe they are all unal-
tion Hfon each o- tcrable, immutable, impaffible : For if , for Example, the Moon
be impaflible , what influence can the Sun or any other Star have
upon her ? it would doubtleffc have far leffe effeft upon her, than
that of one who would with his looks or imagination , lignific a
piece of Gold. Moreover , it feemeth to me, that whilft the Coc-
kftial bodies concarre to the generation and alteration of the
Earth, they themfelves are alfo of neceffity alterable ^ for other-
wife I cannot underftand how the application of the Sun or Moon
t0 the Earth , to efFea produaion , fliould be any other than to lay
a marble Statue by a Womans fide , and from that con)unaion to
expeft ckildren.

Afiiit SiMPL. Corruptibility, alteration, mutation, C^f. are not in

^Iminthe^hoic ^holc Tcrrcftrial Globe, which as to its whole^ is no lefTe eter-
'^'''itfmfltit^^ Moon, but it is generabic and corruptible as ro

p^r^r its external parts j but yet it is alfo true that likewife in them ge-

neration and corruption are perpetual , and as fuch require the
heavenly eternal operations , and therefore It is neceffary that
the Coeleftial bodies be eternal

S AGR- All this is right j but if the corruptibility of the fuper-
ficial parts of the Earth be nowife prejudicial to the eternity of
its whole Globe , yea, if their being generabic, corruptible, alter-
able, &*c. gain them great ornament and perfeaion j why can-
CctUM hiies not, and ought not you to admit alteration, generation, &c. like-
dterabie in their ^. ^j^^ extcmal parts of the Gocleftial Globes , adding to
cm-tv^rd f^ts. ^^^^ ornament , without taking from them perfedion , or berea-
ving them of aaion h yea rather encreafing their effeas , by grant-
ing not onely that they all operate on the Earth, but that they mu-
tually operate upon each other , and the Eaith alfo upon them
all ?

S I M P L. This cannot be , becaufe the generations, mutations,
^c. which we fhould fuppofe v. g. in the Moon , would be vain
and ufelelTe , & natura nihilfrnjira facit. S a G

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

lALOGUF. 1.

rs,
htcd
feof

rand

(ipaf-
: paf-
kthe

Qufe-
tany

ive
an
lific a

Khe

Dther*
Moon
to lay

lot in
tatcr-
Ks to

ige-

r the
' that

Ipcr-

ity of

Sage. And why fliould they be vain and ufeleffe ?
S I M p L. Becaufe we cleerly fee , and feel with our hands, tha

♦ o I M P L. eecaule we cleerly iee , and feel with our hands, that rhc^,H,ra,i», &
all generations, corruptions, ^r. made in the Earth , are all ei-
ther mediately or imniediately dire&d to the ufe, convenience,
and benefit of man ; for the ufe of man are horfes brought forth, 'f
tor the feedmg of horfes, the Earth produceth graffe, and the
Clouds water it i for the ufe and nourifliment of man, herbs, corn,
truirs, beafts, birds, fiflies, are brought forth i and in fum , if
wc fliould one by one dilligently examine and refolve all thefc
thmgs , wc flvjuld find the end to which they are all direfted, to be
tne ncceQity, ufe, convenience, and delight of man. Now of what
uie could the generations which we fuppofe to be made in the
Moon or other Planets, ever be to mankind? unlcffe you fliouId
lay that there werealfo men in the Moon , that might enjoy the
benefit thereof ; a conceit either fabulous or impious.

ted ^-T' J ""^^ °' ' ^^^^ gen^"- ^'"^

u eitner herbs, or plants, or animals, like to ours, or that there »/

arc rams, winds, or thunders thcr<.. as about the Earth, I nci- f'^''
ther know, nor believ. 'nuch lefle , that u isthabited by

men : but yet i underftand not , becaufe there are not genera-
ted things like to ours , that therefore it neceffarily followcth
that no alteration u wrought therein, or that there may not be

«n.lv Tff^' ''''' "''^"S^' g^n"«^> anddiOblve, which are not
onejyuitterentiromours, but excecdinely beyond our imagina- ^f^"""-""-
t.on , and in a word not to be thought of by us. And iff as 1 ''"l.ru^"'"
am certain, that one born and brought up inafpatious Forreft,
ainongft beafts and birds , and that hath no knowledg at all of the

to DC in Na urc , difterent from the Eatth , full of living crea- .f,hc BU-
mcs, which without legs or wings fwiftly move, and not upon 3 °^
thefurfaceouely, as beafts do upon the Earth, but in the very "tj;^'

owcls thereof; and not onely move , butalfo ftay themfelves
and ceafe to move at their plealure , which birds cannot do in the
a«r, and that moreover men live therein, and build Palaces and
Vvities , and have fo great convenience in travailing , that without
the kali trouble , they can go with their Family, Houfe, and
no-le Cities , to places far remote , like as I fay, I am certain,
a pcrfon, though of never fo piercing an imagination , could
never fancy toJiimfelf Fiflies, the Ocean, Ship, Fleets, Arma-
theVt ' '^^'^^ eafily, may it happn , that in

itanc " ' ''y great a fpace , and of a fub-

ters '^^ y^fy different from the Earth , there may be mat-

all o • not only wide off, but altogether beyond

./"^'"Jg^nations, as being fuch as have no refemblance to
s, and therefoi e wholly inexcogitable,in regard, that what we

ima-

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2°K.B. 9,163

rent from oftrs,

G. GhLiLMUSyhis Syfleme.

imagine to our felves , muft neceffarily be cither a thing already
feen, or a compofition of things, or parts of things feen at ano^
ther time h for fuch are the SphinxeSy Sirenes^ Chim^eraSy Cen-
tnursy Sec. ^

S ALV- I have very often let my fancy ruminate upon thefe fpe-
culations , and in the end , have thought that 1 had found fome
things that neither are nor can be in the Moon ^ but yet I
have not found therein any of thofe which I believe are , and may
be there , fave onely in a very general acceptation , namelyjthings
that adorn it by operating, moving and living ^ and perhaps in a way
There way he ffih' Very different from ours , beholding and admiring the greatnefs and
fiances in the b^auty of the World , and of its Maker and Ruler, and with
continual Encomiums finging his prayfes and in fumme (which is
that which 1 intend) doing what facred Writers fo frequently af-
firm , to wit , all the creatures making it their perpetual imploy-
ment to laud God.

Sa.gr. Thefe are the things , which (peaking in general terms,
may be there , but I would gladly hear you inftance in fuch as you
believe neither are nor can be there j which perchance may be
more particularly named.

Salv- Take notice Srf^r<?^/;^ that this will be the third time
that we have unawares by running from one thing to another , loft
our principal fubjea^ and if we continue thefe digreffions , it
will be long ere we come tp a.conclufion of our difcourfe ^ there-
fore 1 ftiould judg it better to riemit this , as alfo fuch other points,
to be decided on a particular occafion.

S /V G R. Since we are now got into the Moon , if you pleafe, let
us difpatch fuch things as concern her , thatfo we be not forced to
fuch another tedious journey.

S ALV. It fhallbe as you would have it. And to begin with
things more general , 1 believe th'at the Lunar Globe is far diffe-
rent from the Terreftrial, though in fome things they agree. I will
recount fitft their rqfemblances , and next their differences. The
The Firft Moon is manifeftly like to the Earth in figure^ which undoubtedly
'XtJE^f^: is fpherical , as may be neceflarily concluded from the afpeft of its
y„hich u that of (mi'sLcc f which ispetfeftly Orbicular, and the manner of its re-
fnl'/"^^^^^^^ the Sun, from which , ifitsfurface were'flat,

nominated bj it would come tobe m in one and the lame time illuminated , and
the Snn, likewifeagain in aricitlier inftant of time obfcured ^ and not thofe
partsfirft, which are fituate towards the Sun, and the reft fuccef-
lively ,i fo that in its oppofition , and not till then , its whole
apparent, circumference is enUghtncd ; which would happen quite
contrary > if thevifible fiirface were concaves namely, the illu-
rhe Second con- ^nation would begin from the parts oppofite or averfe to the Sun,
formitj is the Secondly flic is as the Earth , in her felf bbfcure and opacous , by
Moons being opA' ^j^j^j^ opacity it IS enabled to teceivej and reflet the light of the

€oHs at the EArth, ^ o .

oun 3

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2°K.B. 9,163

efpe-
Jbme

amay
things
ay
and
ith
lich is
tly af-
aploy-

le, let
reed to

with
r diffe-
I will
h The
itedly
a of its
f its re-
^re'flat,
d 5 and
t thofe
Ikccef*
Fwhole
fk quite
the ilUi-
:heSun.
>us, by
of the
Sun 3

Thirdly^ The mat-
tcr of the C^foon u

Eariht

Dialogue I.
Sua j winch were it not fo, it could not do. Thirdly, 1 hold its
matter to be molt denib and folid as the Earth is , which I clearly ^
argue from the unevenncls.of its fiiperficies in moll: places, by means ^'-^y^'
oi the many ^dainencies and cavities ditcovered therein by help q^"'"'"^'^'
the lelej cope : of which eminencies there are many all over it , di-
rcfily rcfcmbliiig our moll (harp and craggy mountains, of which
you (hall there perceive fomc extend and run in ledges of an hun-
dred miles: long ^ ochers are contrafled lato rounder forms j and
thereare alio jnany craggy, folitary, flecp and cli(fy rocks. But
that vyhich there are frequenteft appearances, are certain Banks
(1 uic thi^^'Oid, becaiife 1 cannot thing of another that better ex-
pi;eileth th^m^- pretty high raifed, which environ and inclofe fields
ok feveral.bigneires, and form . fundry figures, but for the moft pare
cneular ^jpany of which have in the'midft a mount raifed pretty
high, an4 iomeifew .are repleniQied with a matter fomewhat ob-
icure, to wit, like to the great fpots difccrned by the bare eye, and
thcle are of the greateft magnitude the number moreover of thofe
tliat arc lefler ^nd lelTer is very great, and yet almoft all cirailar.
r ourthly, like: as the furface of i« ^liftinguiHied into two ^^^'"'^^Z »

principal parts, navn->rV "^^^ ^^^^ Tcrreftrial and Aquatick .: fa ^f,"^"^ U'^IZ
the Lunar lurface we diicern a great diftinftion of fome great fields "^'f^^'"' T^rts %l
more refplendant, and fome lefs : whole afpeft makes me believe '{''''^ ''"^ '^f''''
that that of the Earth would feem very like it, beheld by zny on^^^L^ guf7Z
ixpm the Moon, or any other the like diftance, to be illuminated rCZ^f^^l^ .
by the Sun : and the furface of the fea would appear more ob- ^/^C^^/.t
icure, and that ofthe Earth more bright. Fifthly, like as we from ^/'^^"/^"'r''^"
the Earth behold the Moon, one while all illuminated, another fet^ ''^^
vyinle halti lometimes more, fometimes lefs ^ fometimes horned
iometimes wholly mvifibly^ namely, when its juft under- the Sun t£t]:LZ
Deams io that the parts which look towards tne Earth are dark : ^H^^/ thcM,on,
Thus in every refpeft, one ftanding in the Moon would fee the r"'^"''*'^'?'*
Illumination of the Earths furface by the Sun, with the fame
periods to an hair , and under the fame changes of fieuFes.
Sixtly, & &

S agr. Stay a little, Sahiatm-, That the illumination of
the Earth,as to the feveral figures, would reprefent it felf to a perfon
placed in the Moon, like in all things to that which we difcover in
the Moon, I underftand very well, but yet I cannot conceive how
wl ^ ^^^^^^ done in the fame period ^ feeing that that

^^hich the Suns illumination doth in the Lunar iuperhcies in a
"^^nth, it doth in the Tcrreftrial in twenty four hours.
1 true, the cfFeft of the Sun about the illuminating

cic two bodies, and replenifiiing with its fplendor their whole
jl' • ' difpatch'din the Earth in a Natural day, and in the
ioon in a Month ; but the variation of the figures in which the

^ illumi-

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2°K.B. 9,163

G. G A L 1 L ^ 11 s, his Syjlcme.

illuminated parts of the Tcrreftrial fuperficies appear beheld from
the Moon, depends not on this alone, but on the divers alpcds
which the Moon is ftill changing with the Sun fo that, if for in-
ftance, the Moon punftually followed the motion of the Sun, and
flood,' for example , always in a direft line between it and the
Earth, in that afpeft which we call Conjunfiion, it looking always
to the fame Hemifphere of the Earth which the Sun looks' unto,
flie would behold the fame all light : as on the contrary, if it Ihould
always ftay in Oppofition to the Sun , it would never behold the
Earth of which the dark part would be continually turn'd towards
the Moon, and therefore invifible. But when the Moon is in
Quadrature of the 5un, that half of the Terreftrial Hemifphere ex-
pofed to the fight of the Moon which is towards the Sun, is lumi-
nous i and the other towards the contrary is obfcure : and there-
fore the illuminated part of the Earth would reprefent it felf to the
Moon in a femi-circular figure.

SaGR. I clearly perceive all this, and under ftand very well,
that the Moon departing from its Oppofition to the Sun, where it
faw no part of the illumination of the Terreftrial fuperficies, and
approaching day by day nearer the Sun , (he begins by little and
little to difcover fome part of the iace of the illuminated Earth
and that which appeareth of it Oiall refemblc a thin fickle, in regard
the figure of the Earth is round : and the Moon thus acquiring by
its motion day by day greater proximity to the . Sun, fucceffively
difcovers more and more of the Terreftrial Hemifphere enlightned,
fo that at the Quadrature there is juft half of it vifible, . inlbmuch
that we may fee the other part of her : continuing next to proceed
towards the ConjunSion, it fucceffively difcovers more and more
of its furface to be illuminated, and in fine, at the time of Gonjun-
aion fceth the whole Hemifphere enlightned. And in fiiort, I
very well conceive, that what befalls the Inhabitants of the Earth,
in beholding the changes of the Moon , would happen to him that
from the Moon fliould obferve the Earth h but in a contrary order,
namely? that when the Moon is to us at her full, and in Oppofition
to the Sun, then the Earth would be in Conjunftion with the Sun,,
and wholly obfcure and invifible i on the contrary, that pofition
which is to us a Conjunftion of the Moon with the Sun, and for
that caufe a Moon filent and unfecn, would be there an Oppofition
ofthe Earth to the Sun, and, to fofpeak, Fnll Earth, to wit, all
enlightned. And laftly, look what part of the Lunar furface ap-
pears to us from time to time illuminated, fo much of the Earth
in the fame time fhall you behold from the Moon to be obfcured :
and look how much ofthe Moon is to us deprived of light, io much
of the Earth is to the Moon illuminated. In one thing yet thcfe
mutual operations in my judgment feem to differ , and it is, that it

being

^ well?
vhcre it
^ and
Ik and

HEarth
a regard
Mng by
Rffively
ightned,
ilomuch
proceed
nd more
Gonjun-
fliort, I
" Earth,
him that
ry order,
)pofition
:he Sun,
pofition
and for
>polition
) wit, all
•face ap-
te Earth
^fcured :
To much
ret thefe

that it

D I A L O G U E I. 5^

being fuppofed^and not granted, that fome one being placed in the
Moontoobiervc the Earth, he would every day fee the whole
Terreftrial fupcrficies, by means of the Moons going about the
Earth in twenty four or twenty five hours but we never fee but
half of the Moon, fince it revolves not in it felf, as it muft do to
be feen in every part of it.

S alv. So that this, bcfals not contrarily, namely, that her re-
volving in her felf, is the caufe that we fee not the other half of
her, for fo it would be neceffary it fliould be, if ftie had the Epicy-
cle. But what other difference have you behind, to exchange for
this which you have named ?

S A G R. Let me fee i Well for the prefent I cannot think of
any other.

Salv. And what if the Earth (^as you have well noted) r^^j^^^^
no more than half the Moon, whereas from the Moon one may iee ti^! cMoo»"& tL
all the Earth-, and on the contrary ,all the Earth feeth the Moon,and half o»eij of the
but onely half of it feeth the Earth? For the inhabitants,to fo fpeak, ^^^^/'''^
of the fuperior Hemifphere of the Moon, which is to us invilible,
are deprived of the fic^ht of *wiear*k and there haply are the
AntiSihoHes, Bt.- ^^^^ ^ remember a particular accident, newly
obferved by our Academian^ in the Moon, from whch are gathered prem the Sarth
two necelTary confequences , one is, that we fee fomewhat more fee more than
than half of the Moon^ and the other is, that the motion o{ th^^^l^^f' ^"""^^
Moon hath exa& concentricity with the Earth ; and thus he finds
the Phcenomenon and obfervation. When the Moon hath a cor-
refpondence and natural fympathy with the Earth, towards which
it hath its afpeft in fuch a determinate part, it is neceffary that the
right line which conjoyns their centers , do paffe ever by the fame
point of the Moons fuperficies, fo that, who fo fliall from the cen-
ter of the Earth behold the fame , fliall alwayes fee the fame
DifcHS or Face of the Moon pundually determined by one and
the fame circumference i But if a man be placed upon the Terre-
ftrial furface, the ray which from his eye palfeth to the centre of the
Lunar Globe, will not pafs by the fame point of its fuperficies , by
which the line paffeth that is drawn from the centre of the Earth
to that of the Is4oon, fave onely when it is vertical to him : but
the Moon being placed in the Eaft, or in the Weft, the point of
incidence of the vifual ray, is higher than that of the line which
conjoyns the centres j and therefore the obfcrver may difccrn
fome part of the Lunar Hemifphere towards the upper circumfe^
r^nce, and alike part of the other is invifible : they arc difcerna-
bleandundifcernablejin refpeft of the Hemifphete beheld from
the true centre of the Earth : and becaufe the part of the Moons
circumference, which is fuperiour in its rifing, is ncthertnoft in its
fetting j therefore the difference of the faid fuperiour and infcri-*

G 2 our

G. G A L I L u his Syjieme.

our parts muft needs be very obfervable j certain fpots and other
notable things inthofc parts, being one while difcernablc , and
another while not. A like variation may alfo be obferved towards
the North and South extremities of the fame Dijcus (or Surface)
according as the Moons pofition is in one or the other Seftion of
its Dragons For, if it be North, fomc of its parts towards the
North are hid , and fomc of thofe parts towards the South are
difcpyered, and fo on the contrary. Now that thefe eonfequen-
Two ipjts in thg cesare really true 5. is verified by the Tele f cope •> for there be in
^Te^ct^zt''^^^^^ one of which, when the Moon

{hi hath reff^a to is in tlie meridian , is fituate to the Northwclt , and the other is
th, ''/^^^^ almoft diametrically oppofire unto it 5 and the firft of thefeisvi-

Earth tn her mo- t ^ i r i i t .

tio;j. fible even without the lelejcope ^ but the other is not. That to-

wards the Northweft is a reafonable great fpot of oval figure , fe-
para ted from the other great ones theoppofite oncislefTe, and
alfo fevered from the biggeft 5 and fituate in a very deer field j in
both thgfe we may manifeftly difcern the forcfaid variations , and
fee them one after another now neer the edge or limb of the
Lunar Z)//67^ 5 and anon remote , with fo great difference that
the dift^nce betwiKt the Northweft and the circumiference of the
pifcmh more than twice; as great at one time, as at the other i
and to the fecjond fpot (bepaufe it is neercr to the circuipfe-
rence) fuch mutatiw importeth more , than twice fo much in the
former- Hence its manifeft, that the Moon , as if it were drawn
by % magnetick vertue , conftantly beholds the Terreftrial Globq
with one and the f^me afpe£i:,; never deviating from the fame,

S ^Gil. Oil 1 when will there be an end put to the new ob-
fervgtipAs aud difcOiveries of this admirable Inftrument ?

Sa l v- If this fuceced according to the progreife of other greAt
invention?, it is to be hoped > that in prpccffe of time , onqmay
arrive tq the fight pf things y to us at pjtcfent not to be imagined.
Sixthly , The g^^ r/e turning tQ.Qur firft difcourfe , I fay for the fix^h rcfembl^nce
ft^L'^i^'^^ ^hat as the Moon for agrea^ p^^ri

illuminate. of tim^.j fupplies tb^ \vani; pf the Si4ij> light , and mak^§,}ii
nights: . by the refleaiop, .its own, reafonable clear ^ fp the
Bmh , recpmpp^nce , affprd^thit wkn itftandsin moft ,^^4^
rfiflectif^ rayes^j j^yery rpleqr illumination , ar\4 fo

muchyin myopipioni> greater thw . that w^^^ cpmeth from hep to^
U5,. how much th^lupeffi^iespf thl E^rth is greater tha^t^h.^c

of.the ;Moo-n»:-.;.; : .-.Oj ^.-./.i-Jhiii'^V? :,/X^-"ri'

- S-^Gi^ Hold jthere j Sal<^i^tHS Wd theire, and permit me the
pleafur^jS>f rielating tp you, bow at this firft hint I have penetrated
the caufe of 2^1^ aQejdent , which I have a thoufand times thought
fromfh! sluhm^ "P^"^ fcut cpuld n^vcr find out. You would fay, that the imper-
to the Moon* feet light whickisfeen in the Moon 5 efpecially when it is horned,
• - . comes

Other
, and
wards
face)
ion of
fis the
th. are
quen-
be in
Moon
ther is
e is vi-
p:to-

; , aad
Id h in
) an<i
of the
e that
of the
other i
:mi;ife-
in the
^wn
Pobe
►^T.

?w ob-

i^jnay
gined.

plj^nce
IF psirit
the
r^^the

\M fo

comes from the reflcfiion of the

I ALOG UE.

ri^co^.u V"'L^^"Tr""* ^"^ lig'jt of the Sun on thcSuperfi-
aesof the Earth and Sea , and that light is more clear, by how

expoled to the Mno„ • ^"'^^^"^ ^'^'^ luminous part of the Earth,

&on 1 ^ " i 'llummated part of the Earth beheld ffotn

sTTv ' '"^T^"" °^ ''g^^ ""'^h the more potent.

Inaword .''''r^'""' ^"'^ ^ abouttofay.

andapSenfi t f ? ^ "-^^''^ ^^"'^ with perfons judicious
fonveEd i f ' ^"'*^'»\r^^hertome, for that whilcft pthers
ny times Sei °"'u^ Axiomatical truths , I have ma-

S V. b^ain Tucha.duou, Paradoxes, that

^x S hllZtr AT'' '■^^^^'■^^ "''^i'^h you at the ve-
^i!^^^::!^'''^'^^''''^'^^^ yetcx>ul/lnever beat
* S-I M P i. If you mcanJ-r-y*»"r "oc beingabw t*ip«.fwade .1^^

to K , that you-^« not make them underftand the fameT T
m«ch.wo«dcrthereat , and aai very iioiifident t^jat if thev d.d
Bot underftand u % your demonftriion <your way of ex^rTflJo^

apprehended rt upon the CKplication any Other man - but if

^T'l^-'^^'^T^^^ ' fo'ast^mrt'hemU'
Sf "°"^^^"f^'/" **^his5 for i confefle my

the XTJ^V V for there:a*e in this, andf^me^

wteXKS ;^«^^u«.es, or refemblances, taaby difficulties,
r ,^ ' ""^^^ 5«» *ive gone tWgH thcfll

whe^' J i- '*' 1 fin<J o«fcaoy truth , in the' acqiiift

mit^i^^'""'^ ihtclligentperfons (fuch as your felf)V
tJiat -wiuch.remains Fo.S? ™1 ^^^^^^y bnef ,n d,fpatchi«g
prQc^fefponf^'^; /°;*/^venth coBfor^^^

Moon • J^l c . , > a^favours ; whereby the E^'h

inte^^ heighiiof its illuminadon , by the ^'"'"•'i^J cciiff,.

QbiSwh.K ^'T" ^"'^ 'J*^ Sun, and with its ftadow

able to and although the revenge be not anfwer-

that for i T''^;' that the Moon often continueth, and
fliadow \[f^^^°"able long time, wholly immcrfed in the Earths

P'ed by the Moon j yet, nevertheleffe , having ripect to the

fmal-

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

G. GALiLiEUs,fc<x
e 1 nu^f the bodv of this, in comparifon to the magnitude
Ke ^ther it -not be denied bu't that the and as ic
tre J nrkthis, is very great. Thus much for the.r con-
ruTtiesorrefemblances. It fhould next follow that we difcourfe
fouching their difparity ; but bccaufe SmfUan. will favour U8
his objections againft the former its neceffary that we hear
and examine them , before we proceed any farther.

S AcrAnd the rather, becaufe It is to be fuppofed that
Si JlUiHs will not any wayes oppofe the difparines , and mcon-
gluities betwixt the Earth and Moon , fmcc that he accounts their
fubftances extremely different. • j • .

S I M P r . Amongft the refemblances by you recited , in the pa-
ralle vou make betwixt the Earth and Moon , I find that 1 can
admit none confidently fave onely the firft, and two others i I
grant the firft, namely, the fphcrical figured howbeit, even in
This there is fome kind of difference , for that 1 hold that oi the
Moon to be very fmooth and even, as a looking-glafle , where-
as, we find and feel this of the Earth to be extraordinary montu-
ous and rugged ; but this belonging to the inequality of fuperfi-
de it (hall be anon confidered, ,n another of thofc Refemblan-
Sy iou alledged ; I fhall therefore referve what 1 have to fay
Sereof , till 1 come to the confiderauon of that. Of what you
incrcui, ti Moonfcemeth, as you fay m your fecond

i f mSce, opacousand obfcure in its fclf , like the Earth i I
dmli not any more than the firft attribute of opacity , of which
the Eclipfes of the Sun affurcme. For were the Moon tranfpa-
rent the air in the total obfcuration of the Sun , would not be-
come' fo duskifh, as at fuch a time it is, but by means of the
tranfparcncy of the body of the Moon, arefraaed light would
palTe through it, as we fee it doth through the tWckeft clouds. But
is to the obfcurity , 1 believe not that the Moon is wholly depri-
ved of light , as the Earth i nay, that clarity which is fcen m the
remainder of it. Difcns, over and above the fmall crefccnt en-
liehtened by the Sun , 1 repute to be its proper arid natural hght,
, J f ■ andnntarefieaionof the Earth, which 1 cftcem unable , by
rA«::r:^«afoTof itsafperity (craggineffe) and obfcurity , to reflea the
filmed « h it, \ " . c n. In the third Parallel I alTent unto you in one
"^;t4L.. SI". anddHTcntin -other : I agree in judgingthe body of the
„ rcfi^a th, SHm ^^^^^ folid and hard , like the Earth , yea much more ,

'ri?M/-« for if from Ariftotk we receive that the Heavens are impenet«ble,
,y woven, imp,- and the Stars the moft d^nfe pa^^of H^^^^" ' "^^^ neceffanly

t:fJM follow, that they are ffloft folid and moft impenetrable.

„^ MoCc ^^^^^ ^^J^ ^^^^^j^^^ ^^^^^^^ ^ j^^ ^^^^^^^ ^^^^^ f

to make Pallaces of, if we could procure a fubftance fo hard and fo
tranfparent

nitudc

1 as it
T con-
Tcourfe
rour \i9
rc hear

tthat
icon-
their

the pa-
Klcan
Irs^ I

even in
^£ the
lere-
montu-
^pcrfi*
Pblan-

2 to fay
hat you
: fccond
arth ) t
>f which
tranfpa-
not be-
sof the
t would
ids. But
y depri-
in in the
:cnt cn-
5il light,
le , by
Ac& the

rm one
of the
:h more?
ictrable?
^ffarily

)vd us for
and [o

ALV

D I A L O G U E. I.

S ^Lv. Rather how improper, for being by its tranfparencc.

wholly invifible, a man would not be able without ftumblingat
the threfliolds, and breaking his head againft the Walls, to pais
from room to room. *

S \ G R. This danger would not befall him, if it be true, as fome 7hfM4.cfof
PtripatttiL^f fay, that it is intangible : and if one cannot t^taK^t-
touch it, much Icfs can it hurt him.

S A L V. This would not ferve the turn, for though tlie matter
of the Heavens cannot be touchc, as wanting tangible qualities :
yet may it ealily touch the elementary bodies . and to offend m
it is as tufficient that it ftrikc us, nay worfe, than if we fliould
firikc it. But let us leave thcfe Fallacesy or, to fay better, thefe
in the air, and not interrupt
S I M P L. The queftion which y oia have fo cafually ftarted, is one
of the moft difliculty that isdifputed in Philofophy and I have
on that fubjeft moft excellent conceits of a very learned Doftor
of Fddoua^ but it is not now time to enter upon them. Therefore
returning to our purpofc, I fay that the Moon, in my opinion, is
much more folid than th^ E-^cn, t>nt do «ot inf^r the lame, as you
do, from the cra*gginels and montuofity of its fuperficies ; but The [nper fides of
rather from the contrary, namely, from its aptitude to receive (fas more
we fee it experimented in the harideft ftones) a polifli and luftre ^u%J^l''u{i
exceeding that of the fmootheft glafs , for fuch neceffarily • muft '
its fuperficies be, to render it apt to makefo lively reflection of
the Suns rays. And foj: thofe appearances which you mentioa.
of Mountains, Cliffs, Hills, Valleys, &c. they are all illufions ':
and I have been prefent at certain publick difputes, where I have
ueard it ftrongly maintained againft thcfe introducers of novelties,
that fuch appearances proceed from nothing elfc> but from thcun- MoZ'^lrflihlt
equal diftribution of the opacous and perfpicuous parts, of which ofTf oplcaJ^'Jul
the Moon is inwardly and outwardly compofed : as we fee itf^^^*^'*^'*^?^^^''
often fall out in chrjftal, amber> and many other precious ftones
ot perfea luftre v in which by reafon of the opacity of fome parts,
and the tranfparency of others, there doth appear fcveral conca-
vities and prominencies. In the fourth refemblance, I gr^nt, that
the (upcrficies of Terreftrial Globe beheld from afar, would make
tvvo ditferent appearances, namely, one more clear, the other more ^
dark ^ but 1 believe that fuchdiveifity would fuccccd quite con-
trary to what you fay *, that is, I hold that the furface of the wa-
^er would appear lucid, becaufe that it is fmooth and tranfparent i
^^d that of the Earth would appear obfcure, by reafon of its o-
F^»ty and fcabrofity, ill accommodated for reflefting the light of
^ijn. Concerning the fifth conn^parifon, I grant it wholly, and
am able, cafe the Earth did (hinc as the Moon, to (how the
iametoanyone that fliould from thence above behold it, reprc-

fented

fcntcd by figures anfwcrablc to thole which we Ice in the Moon :
I comprehend alio, how the period of its illumination and varia-
tion of figiue, would be monthly , albeit the Sun revolves round
^ about it in twenty four hours : and laftly, I do not fcruple to

admit, that the half onely of the Moon fceth all the Earth, and
that ail the Earth feeth but onely half of the Moon. For what
remains, I repute it moft falfe, that the Moon can receive light
from the Earth, which is moft obicure, opacous, and utterly un-
apt to reileft the Suns light, as the Moon doth refleft it to us : and
as I have faid, 1 hold that that light which we fee in the remain-
der of the Moons face ^the fplendid crefcents lubduftedj) by the
illumination, is the proper and natural light of the Moon, and no
eafie matter would induce me to believe otherwife. The feventh,
touching the mutual Eclipfes, may be alfo admitted , howbeit
that is wont to be called the eclipfe of the Sun, which you are
pleafed to phrafe the eclipfe of the Earth. And this is what /
have at this time to fay in oppofition to your feven congruities
or refemblances, to which objedions, if you are minded to make
any reply, 1 fliall willingly hear you.

Sal V. If I have well apprehended what you have anfwered, it
feems to me, that there ftill remains in controverfie between uSjCer-
tain conditions, which I made common betwixt the Moon & Earth,
and they are thefe^You efteem the Moon to be fmooth and poliflit,
as a Looking- glafs, and as fuch, able to reflcft the Suns light and
contrarily,the Earth, byreafon of itsmoijtuofity, unable to make
fuchrefleftion: You yield the Moon to be folid and hard, and that
you argue from its being fmooth and polite, and not from its being
montuous j and for its appearing montuous, you aflign as the
caufe, that it.confifts of parts more and lefs opacous and perfpi-
cuous. And laftly, you efteem that fecondary light, to be proper
to the Moon, and not refleded from the Earth ^ howbeit you
feem not to deny the fea , as being of a fmooth furface , feme
kindof refleftion. As to the convincing you of that error, that
the icflection of the Moon is made, as it were, like that of a
Lookine-glafsj I have fmall hope, whilft I fee, that what hath
*JlSaggiatcre,Sc ^^^^ thc'^ Saggi at or and in the Solar Letters of our Com-

tJ^rrt.z^!^'o^ profited nothing in your judgment, if haply

CalfUMs. you have attentively read what he hath there written on this iub-
)cct.

SiMPL. I have pcrufed the fame fo fuperficially, according to
the fmall time of leafure allowed me from more fohd ftudies j
therefore, if you think you can, either by repeating fome of thofe
reafons, or by alledging others, refolve me thefe doubts, I will
hearken to them attentively.

S AJ-V. I will tell you what comes into my mind upon the

inftant,

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

i'> It
asjcer-
Earth)
►oliflit,
5 and
make
id that
I being
as the
perfpi-
proper
It you
fome
ir, that
|o f a
fhath
r Com-
haply
|fub-

Eng to
tudies j
f thofe

Dialogue L' '^j^.' ,

inftaat , and its polliblc it may be a commixtion of my Own d)n-
ceipts 3 and thofe which I have fometime read in the fore-faid
Books , by which I well remember , that I was then perfectly
Satisfied, although the conclufions, at firft fight feem^d unto me
ftrange Paradoxes. Wc cncimvG Simplicius , whether to the ma-
king a reflection of light, like that which we receive from the
Moon , it be necelTary that the fuperficies from whence the refle-
ction commeth , be fo fmooth and poHte, as the face of a Looking-
Glaflb , or whether a fuperficies not fmooth or poliflit , but rough
and uneven , be more apt for fuch a parpofe. Now fuppofing
two reflections fliould come unto us , one more bright , the other
* I fuperficies oppofite unto us , I demand of you,

which of the two fuperficies you think would reprefent it felf to
Our fight , to be the cleareft , and which the obfcurcft.

Sim p t . I am very confident , that that fame , which moft for-
cibly reflefied the light upon me , would flicw its felf in its afpeft
the clearer, and the other darker. .

w!n ^^1^ ^^^^^""^ ^""^^ ' ^^^^^ ^^^'^^ ^^^"g^ y^"^^^ ^ P-^'^ ^

Wall, and let us go ou*i"^o the Court-yard. Com^ Sa^redus^''^^' t%at the
Now hang the gi^fle yonder, againft that fame Wall , on which ^"'"^ ff*rfdce it
the Sun (hines , and now let us with-draw our felves into the fliade
See yonder two fuperficies beaten by the Sun , namely, the Wall
andtheGlaffe. Tell me now which appears cleareft unto you,
that of the Wall or that of the Glaffe ? Why do you not anfwcr

SA GR Heave the reply to who made the quefti-

oinLinaof.?''"'^ own part, am perfwaded upon thi. fmall be-
polX^urface"^'""'"' ' '""^ ^ ^^^^ -

S A L V. What fay you Simplicim , if you were to depaint that
wall and that Glaffe fattened unto it, where would you ufc
your darkeft colours, in defigning the Wall , or elfe in painting
the Looking-C laffe. ^

Simp l. Much the darker in depainting the Glaffe.
J>ALv Now if from the fuperficies, which reprefents it felf
more clear there proceedeth a more powerful refleaion of light.

Simp I,. Very well, Sir, have you ever a better experiment
^nanthis? you have placed us where the Glaffe doth notrever-
wiU you^^Vft ' along with me a little this way ; how,

Chile inaklh" ^^^^ ^'"""^ °^ ^flcaion, which the

SiMPl. 1 dofo. '*

SaGR'

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

G. G A L I L ^ us, hh Syfleme]

S \ G R Why look you, there it is upon the oppofite Wall, ^uft
as big as the Glaire , and little leffe bright than if the Sun had
direftly fhined upon it.

S I M p L. Come hither therefore , and fee from hence the fur-
face of the Gla{fe , and tell me whether you think it more ob*
fcure than that of the Wall.

S A G R- Look on it your felf 9 for 1 have no mind at this time,
to dazle my eyes , and 1 know very well , without feeing it ,
that it there appears as fplendid and bright as the Sun it fclf , or
little leiTe.

SiMPL. What fay you therefore, is the refleftionof aClafTe
leffe powerful than that of a Wall ? 1 fee, that in this oppofite
Wall , where the reflcciion of the other illuminated Wall comes',
together with that of the Glaffe , this of the Glaffe is much
clearer h and 1 fee likewife , that, from this place where I ftand,
thc= gUffe it felf appears with much more luftre than the Wall.

S A T V. You have prevented me with your fubtlety ^ for I flood
in need of this very obfervation to demonftrate what remains.
You fee then the difference which happens betwixt thetworeflc*
fiions made by the two fuperficies of the Wall and Glaffe, per'*
cu ft in the felf-fame manner , by the rayes of the Sun h and you
fee , bow the reflection which comes from the Wall , diffufeth it
fclf towards all the parts oppofite to it, but that of the Glaffe
gocth towards one part oncly , iK>t at all bigger than the Glaffe
it felf: you fee likewife? how the fuperficies of the Wall, beheld
from what part foeVer , alwayes fliews it felf of one and the fame
cleerneffe , and every way , much clearer than that of the Glaffe,
excepting only in that little plaice , on which the Glaffes reflection
reverberates, for from thence indeed the Glaffe appears much more
lucid than the Wall. By thcfe fo fcnfible , and palpable experi-
ments, my thinks one may foon come to know , whether the
reflection which the Moon fends upon us , proceed as f om a
Glaffe , or elfe, as from a Wall , that is , from a fmooch fuperfi-
cies, or a rugged.

S ^ ^^^^ Moon k fclf 5 I tttnk I could not with

my hands more plainly feel the unevcnneffe of its fuperficies , than
I do aow perceive it ,by apprehending your dilcourfc. The Moon
beheld in any pofture, inrefpeft of the Sun and us, fhcweth us
itb rupek-aciv-s 5 touch't by the Subs rayes, alwayes equally clear j
anetfi ct , which anfwers to an hair that of the Wall , which be-
held from what pUcve foevcr , appeareth equally bright , and dif-
fereth from the Glaffe , which from one place onely appeareth lu-
cid y and from all others obfcure. Moreover , the light which
comethto me,. from the refleflion of the Wall , is toUerable,
and weak , in comparifon of that of the Glaffe , which is little

leffe

)fite
[ncsi
lucb
Uidj

kood
ains.
eHe*
per^
I you
sthic
hffc
Haffc
*eld
fame
laffe,
Ption

peri-
:r the

Mth
Plan

th us

fdif-

jblu-
iich

Kle,

little
effe

FUt Looking-

D I A L O G U E L

kffe forcfbit? and ofFcnfivc to the fi ^ht , than that pi^irhary and
direct light of the Sun. And thus without trouble do we behold
the face of the Moon ^ which were it as a G laffe , it appearing to
usbyreafonof its vicinity, as big as the Sun it felf , itsfplcndor
woul4 be abibliitely intolerable , and would reem as if we befield
another Sun. t

Sai.v. Afcribenot, I befeech you Sagrcdtps ^ more to my de-
monftration, than it produceth. I will oppofe you with an inftance,
which I fee not well how you can cafily refolve. You infift upon it
as a grand duTerence between the Moon andGlaffc, that it emits
its reflection towards all parts equally , as doth the Wall j where-
as the Glaffe cafts it upon one onely determinate place j and from
hence you conclude the Moon to be like to the Wall , And not t6
the Glaffe : But I muft tell you , that that fame Glaffe caft^ its
reflection on one place onely , becaufe its furface is flat , and the g^^S" '^^Z h^f^
reflex rayes being to depart at angles equal tothofeof the vdijcs'^'^Jl^'^y'^
of incidence > it muft follow that from a plane or flat fuperficies, vhcg , y^t the
they do depart unitedly towards the fame place o but in regard ^^^"^"^ '""'-^
that the fuperficies of tb* "ft plain, but fpherical , ^and

the incident rayes upon fuch a fuperiicies, being to reflect theni-
felvesat angles equal to thofeof the incidence towards ;lll parts,
by means ot the infinity of the inclinations which compofe the
fpherical fuperficies,therefore the Moon may fend forth its reflecti-
on every way ^ and there is no neceffity for its repercuffion upon one
place onely, as that Glaffe which is flat.

S I M p L' This is one of the very fame objections , which I in*
tended to have made againil him.

S A G R. If this be one , you had need have more of thems yet

I tell you , that as to this firft , it feems to me to make more a-
gainll you , than for you.

S I M P You have pronounced as a thing manifeft^ that the refle-
ction made by that Wall , is as cleer and lucid as that which the
Moon fends forth , and I efteem it nothing in comparifon thereto.

For, in this bufineffe of the illumination , its requifite to refpect,
" and to diftinguifli the Sphere of ASlimty and who queftions rbe fphnc of

but the Coeleftial bodies have greater Spheres of activity , than ^^'vity greater

II thefe our elementary, frail, and mortal ones? and that Wall,

" finally , what elfe is it but a little obfcure Earth , unapt to m:nurj.
^'fliine?

^ \ G R. And here alfo I believe,that you very much deceive your
J^^^' But I come to the firft objecton moved by Sahiatm j and
Iconfider, that to make a body appear unto us luminous, itfuf-
liceth not that fhe rayes of the illuminating body fall upon it,
but it is moreover requifite that the reflex tayes arrive to our
^yc, as ismanifeftly feen in the example of that Glaffe, upon

H i which

whi

G. G A L I L ^ u s, his Syjleme.

without qiicftion, the illuminating layes of

fphrtcal ^laf
. yvoHldbeinvtfible

the Sun do

comei yctnevcrtheleffe, it appea.s not to us bright and (h.n.ng,
JSbiefetoureye in thac particular place where the rcac
a un arriveth. Now let us confider what would lv>ccced were
heglaffeof a fphcrical figure, for withcn.t doubt , we Md
Sthat of the Reflection* made by the whole lurface .llum,na-
t d that to be but a very fmall part which arnveth to the eye
of a particular beholder , by reaton that that .s but an .nconi.de-
vlle^pa" ickofthe whole fpherical fuperficies -the uKhnatton
of which cafts the ray to the particular place ot the eye , whence
the Dart of the fpherical fuperficics , which (hews .t felf Ihining
to the eye , muft needs be very fmall •, all the reft being repre-
d obfcure So that were the Moon fmooth, as a Lodking-
aulfe a very fmallpartwouldbefcenby any particular eye to
be iUuftrated by the Sun , although its whole Hemifphere were ex-
- pofed to the Suns rayes i and the reft would appear to the eye ot
fhe beholder as not illuminated, and theretoreinvifiblei and
finally the wholeMoon would be l.kew.fe mvifible , for fo much
L^' whence the refleaion fiiould come , by reaton of

rfmiJeTln^--^^^^^^ would beloft. AKd as it would be
vSe to the eye , fo would it not afford any light ; for it is al-
r h rTmpoaile, that a bright body Oiould take away our
j^f iTe bv its fplendor , and we not to fee it.

SI' Stay good Sagredui , for 1 fee fome emotions in
he face and eyes of SimfliciHS , which are tome as indices that
he is not either very apprehenfive of , or fatisfied with this which
vou with admirable proof , and abloluie truth have fpoken-
And" yet I now call to mind, that ! can by another experiment
remote all fcruple. I have feen above in a Chamber , a great
fpherical Looking-glaffe i let us fend for it hither , and wh.left it
if in bringing, let Simflicim return to confider, how great the
ch°ityKhich Cometh to the Wallhere, under the penthoufe ,
from the reflection of the flat glalTe.
T T 1 {ce it is little leffe ftiining , than if the Sun had di-

leaiy beat upon Now tell me, iftaking away that fmall

flat Piaffe', we flioul'd put that great fpherical one in the fanic
placIV what eflFect (think you) would its reflection have upon the

"■^''"si^PL? 1 believe that it would eject upon it a far greater and

niorediftafed haht. . n u u u- Cr,

5 ALv. But if the illumination fliould be nothing or fo
fmall , that you would fcarfe difcern it , what would you fay

1" M P L- When 1 have feen the effect , I will bethink felf
ofananfwer. ^^I-V-

jeflc-
■ere

iuld

aina-
fcye

mde-
latibn
bcncc
lining
repre-
iking-

our

he fame
|on the

Iter and

Dialog ur,

S A L V See here is the glaffe , which 1 would have to be placed
cioic to the other. But firft let us go yonder towards the retlection
of that flat one , and attentively obferve its clarity o fee how
bright it is here where it fhines , and how diftiaftly one may dilcern
thefe fmall unevenncifes in the Wall. ^

S I M p L« I have feen and very well obferved the fame, now place
the other glaife by the fide of the tirft.

S ALV.'See whercitis. It was placed there affoon as you be-
gan to look upon the Walls fmall unevenncfles , and you percei-
ved it not , fo great was the encrcafe of the light all over the reft of
the Wall. Now take away the flat glaflc. Behold now all reflc-
flion removed , though the great convex glaffe ftill remaineth.
Remove this alio , and place it there. again if you plcafe , and you
fhall fee no alteration of light in all the Wall. See here thende-
monftrated to fenfe, that the rcflefiion of the Sun, made upon a
fpherical convex glafTe, doth not fenfibly illuminate the places' neer
unto it. > Now what fay you to this experiment ^

S I N^^^L- 1 ^m afaid that there may be fome Leigerdemain ,
ufed in this affair yei^-- ^'^'^^'^'"g ^^^'^ S**^''^ 1 ^ee it dart forth
a Hreat iplendc»r , which dazleth my eyes j and that which im-
ports moft of all , i lee it from what place foever I look upon it^
and 1 fee it go changing fituation upon the fuperficies of the gla^^e,
which way foever I place my felf to look upon it \ a necefTary ar-
gument, thit the light is livelily reflected towards every fide and
confequently,as ftror»gly upon all that Wall , as upon my eye.

S A L V- N^ow you fee how cautloufly and refervedly you ought
to proceed in lending your aflent to that, which difcourfe alone re-
prefentetb to you. There is no doubt but that this which you fay>
carrieth with it probability enough , yet you may fee , how fenii*
ble experience proves the contrary.

Sim PL. How then doth this come to pafe
Salv- 1 will deliver you my thoughts thereof, but I cannoc
tell hbw yoU may be pleafd therewith. And firft, that lively
fplendor which you fee upon the glafs^ and which you thiuk occu-
pieth a good part thereof, is nothing near fo great, nay is very ex-
ceeding firtalU but its livblinefs occafioneth in your eye, (by means
<if the Peflcftion made on the humidity of the extream parts of the
eye-^brows^which diftendeth upon the pupil) an adventitious irradi-
^ation, like to that blaze which we think we fee about the flame of
W candle placed at fome diftance ^ or if y*'^ will you may
r^femble
compai
with

the fame.fcen by ni^ht by the eye it felf, you will doubtlefs com- 7 _
prehend that being irradiated, it appeareth above a thoufand Pjj.^'^";^/^^^^^

times cUritj

uch h

than

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

(J 2 G. G A L 1 L ^ u bis Sjlleme.

times bi^gc I* than the naked and real body : and a like or greater
augmentation doth the image of the Sun make, which you fee in
that glafs. I fay greater, for that it is more Hvely than the flar,
as is manifeft from our being able to behold the ftar with much
lefs offence, than this reflection of the glafs. The reverberation
therefore which is to difpere it felf all over this wall, cometh from
a fmall part of that glafs, and that which even now came from
the whole flat glafs difperfed and reftrain d it felf to a 'very fmall
part of the faid wall. What wonder is it then, that the tirft re-
flection very lively illuminates, and that this other is almofl: im-
perceptible ?

S I M p L- I find my felf more perplexed than ever, and there
prefents it felf unto me the other difficulty, how it can be that
that wall, being of a matter fo obfcure, and of a fuperficies fo un*
polifli'd, fliould be able to dart from it greater light, than a glafs
very fmooth and polite.

SaLV- Greater light it is not, but more univerfalj for as to
the degree of brightnefs, you fee that the refleSion of thi^ fmall
flat glafs, where it beamed forth yonder under the fliadow of the
penthoufe, illuminateth very much h and the reft of the wall which
receiveth the reflection of the wall on which the glafs is placed,
is not in any great meafure illuminated, as was the fmall part on
Which the reflection of the glafs fell. And if you would under-
ftand the whole of this bufinefs, you muft confider that the fuper-
7he reflex hght ficies of that walfs being rough, is the fame as if it were compo-
9f uneven boMeiyii innumerable fmall fuperficies, difpofed according to in-

7Zn thaTcffhi numerable diverfities of inclinations : amongft which it neceffa-
fmooth,&why. j-iiy l,appens, that there are many difpofed to fend forth their
reflex rays from them into fuch a place, many others into another:
and in fum, there is not any place to wluch there comes not very
many rays, reflected from very many fmall fuperficies, difperfed
throughout the whole fuperficies of the rugged body, upon which
the rays of the Sun fall. From which it neccffarily follow-
eth , That upon any, whatfoever, part of any fuperficies,
oppofcd to that which receiveth the primary incident rays,
there is produced reflex rays , and confequcntly illumi-
nation There doth alfo follow thereupon , That the fame
body upon which the illuminating rays fall , beheld from
whatfoever place, appeareth all illuminated and fliining : and
therefore the. Moon , as being of a fuperficies rugged and
The Mot>n,ifit not fmooth , beameth forth the light of the Sun on every
^^^^ beholders appeareth equally lucid. But if

vr^bur ^ the furfacc of it, being fpherical, were alfo fmooth as a glafs, it
would become wholly invifible *, forafmuch as that fmall part,
froi? which the image of the Sun fliould be reflefted unto the eye

I ALOO UE.

er
tt in
ftar,
[luch
ition
from
from
inall
ft re-
lim-

there

fmall
f the
vhich
aced,

per-

uper-
►mpo-
ro in-

pieir

Jther:
t very
>erfed
which
Jlow-

rays ,
Ulumi-
ifilime
Trom
: and
I and
fvery

p '^^

ifs, it
•artj

of a particularpcrfon^by reafon of its great diftance would be in-
vifible, as 1 have faid before.

Sim PL* 1 am very apprehenfive of your difcourfci yetme-
thinks I am able to refolve the fame with very little trouble j and
eafily to maintain, that the Moon is rotund and polite, and that it
refle£i:s the Suns light unto us in manner of a glafs , nbr there-
fore ought the image of the Sun to be feen in the middle of it, for-

afmuch as the fpecies of the Swn it felf admits not its fmall figure
" to be feen at fo great a diftance, but the light produced by the
" Sun may help us to conceive that it lUuminateth the whole Lu-

nar Body : a like efFcft we may fee in a plate gilded and well

poUifli'd, which touch't by a luminous body, appeareth to hnn
" that beholds it at fome diftance to be all ftinihg j and onely near
^^at hand one may difcover in the middle of it the fmall image of

the luminous body.

Salv- Ingenuoufly confeffing my dnllnefs of apprehenfion,
I muft tell you, that 1 underftand not any thing of this your dif-
Gourfe, fave onely what concerns the gilt platd : sind if you permit
me to fpeak freely, 1 hav-s -g*^*^ conceit th^t yo« alfo andeiftand
not the fame, buc have learnt by heart thofe words written by iome
one out of a defire of contradiSion, and to (hew himfelf more intel-
ligent than his adverfary ^ but it muft be to thofe, which to appear
alfo more wife, applaud that which they do not underftand, and
entertain a greater conceit of perfons, the lefe they are by them
underltood : and the writer himfelf may be one of thofe (of which
there are many^ who write what they do not underftand, and somtwritewhM
confequently underftand not what they write. Therefore, o- »»dafiMnd
mitting the reft, 1 reply, as to the gilt plate, that if it be flat and I'^lrfJ'^'^Z
not very big, it may appear at a diftance very bright, whilft a great what they write.
light beameth upon it , but yet it muft be when the eye is in a de-
terminate line, namely in that of the reflex rays : audit will ap-
pear the more (hitting, if it were g» of filver, by means of its
being burnilhed> and apt through the great denfity of the metal,
to receive a perfect poiilh. And though its fuperficies, being very
well brightned, were not exaftly plain, but (hould have various in-
clinations, yet then alfo would its fplcndor be feen many ways j
uamely, from as many places as tht various refleftions, i«ade by
the feveral fuperficies, do reach : for therefore are Diamonds T)ian,onds grouni
ground to many fides, that fo their pleafing luftfe itfight be beheld ^^^*v^s fides, &
from many places. But if the Plate Were very big, though it (hould ^'
be all plain, yet wo'jid it not at a diftance appear all over fliining :
and the better to exprefs my felf, Let U9 fuppofe a very large gilt
plate expofed to the Sun, it will fliew to' an eye far diftant, the
image at thr Sun, to occupy no more but a certain part of the faid
plate j to wit, that from whenc-e- the reflefKon of the incident

folar

d by courtesy of the Royal Library, Copenhage

■ Silver hurmfhei
appears more oh-
fcu-t^ thu > the MP t
^Hrrji{hed^& wh;-.

BurfiifhU Steel
beheld f>^<^f» one
piare appears terj
bright , and. from
another, verj ob-
[cure.

G. X) A L 1 L u s, his Sjfleme.

folar rays come : but it is true that by the vivacity of the light, the
faid image will appear friiigcd about with many rays, and fo will
fecm to occupic a far greater part of the plate, than really it doth.
And to (hew that this is true, when you have noted the particular
place of the plate from whence the refleftioii cometh, and concei-
ved likewife how great the (hining place appeared to you, cover the
greater part of that fame fpace, leaving it only vifible about the
midft j andall this fliall not any whit diminifli the apparent fplcn-
dor to one that beholds it from afar j but you fliali fee it largely
difpers'd upon ihq cloth or other matter, wherewith you covered
it. If therefore any one,by feeing from a good diftance a fmall
gilt plate to be all over fhining, fhould imagine that the fame
would alfo even in a plate as broad as the Moon, he is no lefs de-
ceived, than if he {hould believe the Moon to be no bi^^ger than
the bottom of a tub if again the plate were turn'd into a fphe-
rical fuperficies, the refleSion woulcf be feen ftrong in but one fole
particle of it i but yet by reafon of its livelinefs, it will appear
fringed about with many glittering rays : the reft of the Ball would
appear according as it was burnilhed j and this alfo onely then
v^hen it was not very much poHflied, for fliould it be perfectly
brightned, it would appear obfcure. An example of this we
have dayly before our eyes in filver veffels, which whilft they arc
only boyrd in the Argot and Salt, they are all as white as fnow,and
do not reflect any image h but if they be in any part burnifli'd, they
become in that place prefently obfcure;and in them one may fee the
reprefentation of any thing as in Looking. glaffes. And that chan-
to obfcurity, proceeds from nothing elfe but the fmoothing and
plaining of a tine grain, which made the fuperficies of the lilve r
rough, and yet fuch, as that it reflected the light into all parts,
whereby it feemed from all parts equally illuminated : which
fmall unevenncfTes, when they come to be exquifitely plained by
the burnifli, fo that the reflection of the rays of incidence are all
directed unto one determinate place h then, from that fame place,
the burnifli'd part fliall ftit w much more bright and fhining than
the reft which is onely whitened by boyhng ^ but from all other
places it looks very obfcure. And note, that thei diverfity of
fights of looking upon burnifli'd fuperficies, occafioneth fuch
difference in appearances, that to imitate and reprefent in picture,
g' a polifli'd Cuirace, one muft couple black plains with white
onelidcways to the other? in thofe parts of the arms where t
light fdllech equally.

S \ G R. If therefore thefe great Philofophers would acquiefe
in granting, that the Moon, Venus and the other Planets, were not
of fo bright and imooth a furface as a Looking-glafs, but wanted
fome fmall matter of it^namely^were as a filver plate, onely boyled

white-^

I A L O G U E

,0^

, the

0 will
tdoth.
Kular

concei-
ver the

^plen-
largely
:overed
a fmall
e fame
els de-
er than
a fphe-
►ne i'ole
appear

1 would
iy then
^rfectly
this we
hey arc
owjand
i*d5 they
I fee the
fcchan-
mg and
z filver

I parts,
l^which
Iwby
■e all
Pplace,
^ than

II other
rfity of
th fuch
picture,
^white,

the

white -y but not burnifhed , would this yet fuffice to the making
of It vifible, and apt for darting forth the light of the Sun ?

Sal V. It would fufficc in part, but would not give a light fo
ftrong, as it doth being mountainous, and in Yum, full of
eminencies and great cavities. But thefe Philoiophcrs will never
yield it to be lefTc polite than a glaffe s but far more , if more it
can be imagined ^ tor they efteeming that to pcrfefi bodies perfect
figures are moft Tutable \ it is neceffary, that the I'phcricity of thole
Ccjelefiial Globes be moft exaft \ befides , that if they (hould
grant me fome inequality , though never fo fmall , I would not
fcruple to take any other greater \ for that fuch perfcdion confift-
mg in indivifiblcs , an hair doth as much detraft from its perfection
as a mountain.

Sagr. Here I meet with two difficulties, one is to know the
reafon why the greater inequality of fuperficies maketh the ftron-
ger refleaion of light \ the other is , why thefe ?eri^ateuc\ Gen-
tlemen are for this exaft figure.

SaLV. I will anfwer to the firft i and leave to Simplitivys the rherKorer^nih
care of making reply tt> recondi You muft know therefore, fupsrjictes make
that the fame fuperficies happen to be by the fame light more or leG f/^^X
illuminated , according as the rayes of illumination fall upon them (cfHo^igh.
more or lelTe obliquely fo that the greateft illumination is where
the rayes are perpendicular. And fee , how 1 will prove it to your X thlTbTZ
fenfe. I bend this paper, fo, that one part of it makes an angle "''^ ^^'7-
upon the other : and expofing both thefe parts to the refleaion of
the light of that oppofite Wall , you fee how this fide which re-
ceiveth the rayes obliquely , is lefTe (hining than this other , where
the reflection fals at right angles , and obferve, that as I by .
degrees receive the illumination more obliquely, it aroweth
weaker. ^ ^

Sagr. 1 fee the effect , but comprehend not the caufe.

SaLv« If you thought upon it but a minute of an hour, you
-would find it i but that I may not wafte the time, fee a kind of
aonaonftratipn thereof in Fi^. 7.

S A G R. The bare fight of this Figure hath fully fatisfied me,
thererore proceed.

S I MPL. Pray you let me hear you out , for I am not of fo
quick an apprehenfion.'

\ Sal v. Fancie to your felf, that all the paralcl lines, which you
^eetodepartfromtheterms A. B. are the rays which fall upon the .

asTJ^' ^"8'^^ '"^""^ ^'^^ ^' hang S^i^:^:'^^

. • O, now do not you fee that a gteat part of thofe rays which ^^/^'
peircec.D.pafsby vvithouttouching aO? If therefore D. O.
De illummj^^ed by fewer rays, it is very reafonablc, that the light
eecived by-it be more weak. JiCt us return now to the Moon,

I which

G. Galil/eus, hh Syjleme.

which being ofalpheiical figure, if its fuperficies were fmooth, a$
this paper, the parts of its hemifpherc iiluminatcd by the Sun,
which are towards its extremity, would receive much lefs light,
than the middle parts the rays falling upon them moft obliquely,
and upon thefe at right angles ^ whereupon at the time of full
Moon, when we lee almoft its whole Hemifpherc illuminated, the
parts towards the midft, would fliew themlelves to us with -more
fplendor, than thofe others towards the circumference : which is
not fo in efFe£l. Now the face of the Moon being reprefented
to me full of indifferent high mountains, do not you fee how their
tops andcontinuatciidges, being elevated above the convexity of
the perfeft fpherical fuperficies, come to be expofed to the view
of the Sun, and accommodated to receive its rays much lefs ob-
liquely, and confequently to appear as luminous as the reft ?

SagR- All this 1 well perceive : and if there are fuch moun-
tains, its true, the Sun will dart upon them much more direftly
than it would do upon the inclination of a polite fuperficies : but
it is alio true, that betwixt thofe mountains all the valleys would
become obfcurc, by reafoa of the vaft (hadows, which in that
time would be caft from the mountains, whereas the parts towards
the middle, though full of vialteysand hills, by reafon they have
the Sun elevated, would appeac without (hadow^ and therefore
more lucid by far than the extreme parts, which are no lefs diffu-
fed with (hadow than light, and yet we can perceive no fuch di&-

rei;ice. ^ ^

S I M P L. I was rumuia ting upon trie like difficulty.
S ALV- How much readier is Simpliciu^ to apprehend the ob-
jeSiotts which favour the opinions of Ariflotle^ than their foluti-
ons ? I have a kind of fulpition, that he ftri,ves alfo fometimes to
diflemble them j and in the prefent cafe, he being of himfelf able
to hit upon the doubt, which yet is very ingenious , I cannot be-
lieve but that he ajfo was advifd of the anfwer j wherefore I will
attempt to wreft the fame ^as they fay) out of his mouth. There-
fore tell me, Simplicn^:, do you think thete can be any fliadowt
where the rays of the Sun do fhine ?

S I M p L. I believe, nay 1 am certain that there cannot^ for that
it benig the grand kuninary^ which with its rays driveth away dark'
nefs, it isimpoflible any tenebrofity fhould remain wfeere it coib-
eth V moreover, we have the definition, thatTe«cfcri€ jknt pri^a-
tio In mink,

S\Lv. Therefore the Sun, beholding the Earth, Moon or <y
ther opacous body, never feeth any of its ftiady parts, it not ha-
ving any other eyes to fee with, fave its rays, the conyeycrs oi
light : and confequently, one ftanding in the Sun would never
fee any thing of umbrage, forafmuch as his vifive rays would ever

I A LOG UF.

accompanied with thole illaniinating beams of the Sun.
S I M p L. This is true , without any contradiftion.
Sal v. But when the Moon is oppofite to the Sun, what dif^
iercnce is there between the traft oi the rayes of your fight , and
that motion which the Suns rayes make ?

S I M P L. Now I underftand you for you would fay , that the
rayes of the fight and thofe of the Sun, moving by the fame lines,
we cannot perceive any of the obfcure valleys of the Moon. Be
plcaled to change this your opinion , that 1 have cither fimulation
or diQunulation in me for I proteft unto you , as I am a Gentle-
nian, that I did not guelTe at this iolution , nor ftould I have
thought upon it , without your help , or without long ftudy.
11 ^j^*^^* The refolutions , which between you two have been
alledged touchmg this laft doubt, hath, to fpeak the truth, fatisfi-
cd me alio. But at the fame time this confideration of the vi-
iible ray^s accompanying the rayes of the Sun , hath begotten in me
another icruple , about the other part , but I know not whether I
can expreffe it right , or no : . for it but juA now comming into my
muid , I have not yet m^^*^'"^'^*^*^ "^y mind .- but let us fee if
we can , all togechcr , make it intelligible. There is no queftion,
but that the parts towards the circumference of that poliOi't^but not
burnifh't Hemifphere, which is illuminated by the Sun, receiving the
rayes obliquely, receive much fewer thereof, than the middle^
moft parts , which receive them direftly. And its poflible , that a
trad or Ipace of ^. g. twenty degrees in breadth, and which is to-
wards the extremity of the Hemifphere, may not receive more rays
than another towards the middle parts, of but four degree broad :

0 that that doubtlefs will be much more obfcure than thisi and
luch ,t will appear to whoever fliall behold them both in the face,
or (aslmay lay) in their fulj magnitude. Butif the eye of the
beholder were conftituted in fuch a place, that the breadth of the
twenty degrees of the obfcure fpace, appeared not to it longer
than one of four degrees, placed in the midft of the Hemifphere,

1 hold It not impoffible for it to appear to the faid beholder e-
qually clear and lucid with the others becaufe, finally, between
two equal angles, to.wit, of four degrees kpiece, there come to

I'^fleftions of two equal numbers of rayes : namely,
tnolc which are refleftcd from the middlemoft fpace, four degrees
|n breadth , and thofe reflefted fron^ the other of twenty degrees,
fiKh compreflion, under the quantity of four degrees : and

P J ^fi^^^^tion fliall the eye obtain , when it is placed between the
^1 J Hemifphere, and the body which illuminates it i for then the
ig t and raves move in the fame lines. It feemeth not • impoflible
eretore , but that the Moon may be of a very equal fuperficies;
and that nevcrthelefle , it may appear when it is at the full , no left

I % light

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

G. GALiLiEUSy his Syjieme.

light in the extremities , than in the middle parts.

SalV. The doubt is ingenious and worthy of coniideration ^
and as it but. juft now came into your mind unawares , fo 1 will
like wife anfvver with what firft comes into my thoughts , and it may
happily fall out , that by thinking more upon it , 1 may ftumblc
upon a better reply. But before, that 1 labyrinth my iclf any far-
ther , it wodld be ncceflary, that we affure our felvcs by fomc ex-
periment, whether your objefiion prove in cffc£r , what it fecmcth
to conclude in appearance^ and therefore taking once more the
fame paper , and making it to incline , by bending ^4ittle part
thereof upon the remainder , let us try whether expofflig it to the
Sun , fo that therayes of light fall upon the Icifer part direftly,
and upon the other obliquely ^ this which receiveth the raycs direfl:-
ly appe^eth more la-cid3 aiaid fee here by.manifeil experience,
that it h notably mpre.clear. Now if your ob jeftion be eonclufive,
it will follow , that ftooping with our eyefo, that in beholding
the other greater part, lels illuminated, in compreffion orfore-
fliortniiig^ it appear unto us no bigger than the other, more fliining',
and that cpnfcqaeutJy 5 it be not beheld at a greater angle than
that ^ it will nccejSaiily eniW, I fay , that its light be encreafed, fo
that it do fecm to us ^s bright, as the other. See how I behold, and
look upon it fo obliquely , %\m it appcarcth to mc narrower than
the other V but yet>^nbtwitliftanding its oblcurity , J^th not to
my perceiving , at aU grow clearer . Try now if the fanie fuccced

* S AGX^.*^^^'^^^^'^^ and though I have ftooped with

nayVye , ye4canno4: I fee the faid fuperficies encrcafe in light or
clarity j nay me thinks it rather grows more dusky.

S A.L Y. We are hitherto confident of the invalidity of the ob-
jefiipn 5 In the ne^^t place, as to the folution , I believe, that, by
reafpn the Superficies of this paper is little lefTe than fmo'oth , 'the
rayes are very fewj whicji be rcfleded towards the point of inci-
dence , in comparifo^ of the multitude , which are refleftcd to-^
wards the oppoiite parts h and that of thofc few more and mor
«ue loft 5 the nearer the vifive rayes approach to thofe lucid rayes
of incidence , and becaufe it is not the incident.rayes , but thofe
which arc reflefted to the eye , that m>ke the ob)ea appear lu-
minous h therefore, in ftooping the eye, there is more loft than got,

you your felf confeflc to have fcen in looking upon the obfcu-
ver part of the paper.

. Sagi\. 1 reft fatisfied with this experiment and reafon :. It re-
mains now, that Simplici^ anfwer to my other queftion , and tell
me what Qioves the Feripatetickj to require this fo cxaft rotundity
in the Coeleftial bodies.
Simp l. The Coeleftial bodies being ingenerable,inalterable,;m-

paifibl

Dialogue L

cth
the
ait
Ffche

[ireft.
encc,
tifive,
ilding
fore-

Bian

P.ro

5 and
Indian

icceed

44"
»0|

>le,

pafllble, immonAj&c. they muft needs be absolutely pertcd^ and p^^fcsi fphmckf
their being ablolutc perfedi:,ncceffarily implies that there is in them ^^fcrtlcd n
all kinds of perfeaion s and confequently,that thek figure be alfo
perfea, that is to lay , fpherica! , and abfolutely and perfeftly ^icks.
fphcrical , and not rough and irregular.

S A I. V. And this incorruptibility , from whence do you pro\rc
it ?

S I M p L. Immediately by its freedom from contraries;> and me-
diately , by its fimple circular motion.

S A L V. So that^ by what I gather from your difcourfe , in ma- The F/£Hrs
king thecflbnceof the Coeleftial bodies to be incorruptible, inal- f^l'^f
tcrable, ^r, there is no need of rotundity as a caufe , or requi- L"4V&'>«! '
fite 5 f3r it this (hould caule inalterability , we might at our plea-
fure make wood, wax, and other Elementary matters, incorrup-
tible, by reducing them to a fpherical figure.

S i M p L. And is it not manifeli that a ball of Wood will better
and longer be preferred, than an oblong , or other angular fi-
gure , made of a like quantity of the fame Wood.

Sal V. This is moft uei^^^ ^ »at yet it not of corruptible
become incorrup«^*«S but ftill remains corruptible, though of a
much longer duration. Therefore you ftiuft tiote, that a thing cor- corruptibility «
ruptible , is capable of being more or leffe fuch , and we may '■'"^ ^'^^^
properly fay this is leffe corruptible than that \ as for example, the fjo^Iltmi [
Jaffer^ than the fietra Sitena j but incorruptibility admits not '
of more, or leffe. fo as that it may be faid this is more incorrupti-
ble than that, if both be incorruptible and eternal/ The diver- perfeaion of
fity of figure therefore cannot operate : ia^e onely in matters ca- h^^re , cperdteth
pable of more or Icffc duration but in the eternal , which can- Meslll^miJZ
not be other than equally eternal , the operation of figure ceafeth. rr.rw.
And therefore , fince the Coeleftial matter is not incorruptible by
figure , butotherwayes no man needs to be fo folicitous for this
perfeft fphericity ; for if the matter be incorruptible , let it have
what figure it will , it fliall be alwayes fuch.

S AGR But 1 am confidering, another thing, and fay, that if
we ihould grant the Ipherical figure a faculty of conferring tncor- £^rc confcrrcth e-
niptibihty, all bodies of whatfoever figure , would be incorrupti- Tullietrtf'
We foralmuch as if the rotund body be incorruptible , corrupti- '
bility viould then fubfift in tbofe parts which alter the pcrfeft ro-
tundity ^ as for inftance , there is in a Dh a body perfeftly round,
*^d, as liich, incorruptible h therefore it remaineth that thofe an-
l^^^ corruptible which cover and' hide the rotundity ^ fo that
tftenioft that could happen, would be, that thofe angles , and
Vto la fpeak) excrefcencies, woukf corrupt. But if we proceed to a '
more iftwa^d confKfcration , that m fbofe parts alfo towards the
ingles* there ar^ compiifed other kffer bak of the fame mattei* ^

and

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

G. GAlil^us, Us Syjleme.

..^ therefore they alio , as being round , mult be alio mcorrup-
tible V and likewlfe in the remainders, which environ theie eight
lefTer Spheres , a man may underftand that there are others : fo
that in the end, relolving tlie whole Die into innumerable balls,
it muft necelTarily be granted incorruptible. And the fame dii-
courfe and refolution may be made in all other figures.

S A L V. Your method in making the conclufion , for if <v:g, a
round Chryftal were^by reafon of its figure,incorruptiblej namely,
receivedfrom thence a faculyof refifting all internal and external
alterations, we fhould not find, that the )oyning to it other Chry-
ftal , and reducing it -z^.. into a Qube , would any whit alter it
within, or without ^ fo as that it would thereupon become lefle
apt to refift the new ambient , made of the fame matter , than it
was to refift the other , of a matter different i and efpecially, if
it be true , that corruption is generated by contraries , as An--
jiotle faith i and with what can you enclofe that ball of Cryftal,
that is leffe contrary to it, than Cryftal it felf? But we are not a-
ware how time flies away , and it will be too late before we come
to an end of our difpute , if we fliould make folong difcourfes ,
upon every particular v befides our memories are fo confounded
in the multiplicity of notions , that 1 can very hardly recal to
mind the Propotfiions , which I propofed in order to Simpltcimi
for our confideration.

S I M p 1- 1 ^^^y ^^"^ remember tnem : And as to this particular
queftionof the montuofity of the Moon, there yet remains un-
anfwered that which 1 have alledged , as the caufe , (and which
may very well ferve for a folutionj of that Phenomenon , faying,
that it is an illufion proceeding from the parts of the Moon, be-
ing unequally opacous , and perfpicuous.

S A G R. Even now, when SimphciHs afcribed the apparent Pro-
tnberancics or unevenneffes of the Moon (according to the opinion
of a certain f^r/p^/^/Ki^ his friend) to the diverfly opacous, and
Mother of FeAYi'^^x(^\c\io\xs parts of the faid Moon, conformable to which the like
Accmmodated to iHufions are feen in Cryftal, and Jems of divers kinds, I bethought
imitate the appa^ felf of a matter much more commodious for the reprefenting
cfthe Moons fur^ fuch cfFcfls h which IS fuch, that I verily beheve , that that Philofo-
f'*^^' pher would give any price for if, and it is the mother of Pearl, which

is wrought into divers figures , and thougk it be brought to an ex-
trcine evenneflc, yet it feemeth to the eye in feveral.parts , fovari-
oufly hollow and knotty, that we can fcarce credit our feeling of
their evenneffe,

S A L V. This invention is truly ingenious *, and that which hath
not been done already , may be done in time to come , and if
there have been produced other Jems , and Cryftals , which have
^lothing to do with the illufions of the mother of Pearl , thefe may

aft be alfo

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Images reproduced by courtesy of the Royal Library, Copenhac
2°K.B. 9,163

I A L O G U E.

rrup'-

: fo
balls,

g. a

l^ly,
|kial

!hry-

&nit

Plal,

lot a-
come

Pfes 5
M

cal to

lar
as un-
which
aying,
I, be-

pinion
) and
le like
lought
bating
^lofo*
bich

ICX-

Kari'
of

tiath
and if

bave
lay
be

be produced alio \ in the mean time , that I may not prevent any
one , I will lupprefle the anfwcr which might be given 5 and onely
for this time betake my lelf to fatisfie the objeSions brought bv
Simplicim. \ fay theccfore , that this reafon of yours is too ge-
neral 5 and as you apply it not to all the appearances one by one i
which are feen in the Moon, and for which my felf and others
are induced to hold it mountainous , I believe you will not Hnd
any one that will be iatisfied with fuch a doftrine ^ nor can I think,
that eicher you , or the Author himfelf , find in it any greater
quietude, than in any other thing wide from the purpofe. Of the The apparent nn-
very many feveral appearances which are fccn night by night in cve>mejfes of the
the courfe of Moon, you cannot imitate fo much as one, by making
a Dan at your choice, more or lets opacous and pcrfpicuGKi^, and more a»Aufs opd'
that isofapolite fuperficies^ whereas on the contrary, one may ^^'^y^^P^r^^^^^^itj'
make Balls of any folid nutter whatlbever, that is not tranfparent, jpeaslfthMool]
which onely with emiaencies and cavities, and by receiving the il- "^'^^^^^ ^'^^
lumination feveral ways, (hall reprefent the fame appearances and
mutations to an hair, which from hour to hour are difcovercd in ^Arsons sppeMra^
the Moon. In theapi. yo» J^<^g«^s Hills expofed to from Jphich the

the Suns light, to be vf ryftiining, and after them the pfo;ca4ans mommftty
of their Oiadows very obicure j you fliall fe<f tbcm greater and Icfs, "
according as the faid emmcncies ihall be more or lefs diftartt from
the confines which diftinguifli the parts of the Moon illuminated^,
from the ofc^cure : you (hall iee the fame term and confine, not
equally diftcnded^ a^ it would be if the Ball were polifli'd, but
crape and riigged. iYou fhallfee beyond thefameterM, in thfe
aaii paft& <pf the Moonmajiy bright prominencies, and difiina
troni the reft of the illuminations; you (hall fee the (liadowi ia-
lor^faid, according as the illumination gradually rifeth, td demii.
ttilUbyde^^ea, till.iib(3y wlwllydi^^ V nor are there any of
them to be feen when the whole HcmifpbeTc is eniightned. ^
gain on the contrary, in the iigiits paffage tow^irds the other He-
Wfph^K of the Moonryou fliall again obfcrve the fame eminen-
9es th^t^er^ sxarked, and y<m ffiall fee the pfoje&ons of theft
fliadows to be made a contrary way, and to decreafe by degrees t
pf whiGtLdiu:igs, onc©borel fay, you cannot fliew m^ fo much as
^ in }{i)iirb\chat are opacous and pcrfpicuous.

Sag One of thcni certairtly he may imitate, narnely, that of
^ne Full-Moon, when by reafon of its being all illuminated, there
*s not to be feen cither fliadowy or other thing, which receiveth
^'^y altcf atioD from its eminencies and cavities. But I befeech
y^^-i Sal^iatm^ let us fpend no niore tiJ»^ this Argument, for
a perioathat hath had but the patience to make obfervation of but
oneor twiftt^anations, and is not fatisfied with this moft fenfibfe
^ruth , .may-wdl be adjudged void of all judgment i and upon

fucb

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

72 G. G A L 1 L ^ u bis Sj'jlerae,

futh why fliould wc throw away our time and breath in vain ? ^
S I M p L. I ii^uft confcis I have not made the obiervations, fof
thatlnevei had fo much curio fity, or the Inftru men ts proper for
the bufinefs i but I will not fail to do it. In the mean time, wc
may leave this queftion in iufpenle, and pals to that point which
follows, producing the motives inducing you to think that the
Earth may refleft the light of the Sun no lefs forceably than the
Moon, for it feems to me fo obfcure and opacous, that I judg fuch
an eftca altogether impoffible.

Salv. Thecaufe for which you repute the Earth unapt for
illuminatioua may rather evince the contrary : And would it not
be ftrange, Simplicim^ if I ftiould apprehend your difcourfes bet-
ter than you your felf ?

S I M P L. Whether 1 argue well or ill, it may be, that you may
better underftand the fame than I ^ but be it ill or well tharl
difcourfe, I (hall never believe that you can penetrate what I mean
better than I my felf.

Salv. Well, I will make you believe the fame prefently. Tell
me a little, when the Moon is near the Full, fo that it may be feen
by day, and alfo at midnight, at what do you think it more fplen-
did, by day or by night ? uiiLri; /

rheu^oonar.. » I M p L, By night, without all comparifon And methinks
fc^n brighcer hj the MooH refcmblcth that pillar ot Clouds and piUar of Fire,
night «^'^«^;^'*/ ^ijich guided the If raelites which at the prefence of the Sun
appeared like a Cloud, but in the night was very glorious. Thus
ThetM^oMh^ i have by day obferved the Moon amidft certain fmall Clouds
/£ ^oZ )uft as if one of them had been coloured white, but by night
UttU cloud, jbines with much iplendor. ^ ^ ^

, S A vv .So that if you had never happened to fee the Moon
iave onely in the day time, you would not have thought it more
jCbining than one of thofe Clouds.
I S iMf^h' verily believe I fliould not.
;. Salv. Tell me iiow^ do you believe that the Moon is really
more^iniogin thf ftigbt than;4ay,. or that by fome ^cdident ic
feemeth; fo ? Ai^'yvs^ oJ Us. . /x.w vir. y .r: •)d oi ev

' . S I ift ^ V I am ofrppinicrti, t6at it refplends in it felf as rfiuch in
the day ks night, but that its light appears greater by night, be^
caufe we behold it. in the dark mantle of Heaven j and in the day
time, the whole Atipofphere being very clear, fo that fhc little
exccedeth it in luftre,, flie feems to us much lefs bright.

S A I, v.. Now tell me j have ypu ever at midnight feen the Tcr-
^^^■^APHe illuminated by the Sun ?

h^. ^ ^' l!^,hi$ feemeth to me a queftion riot to be ask'd, unlefs
iii )eft, pr of fome perfon known to be altogether void of fenfe.
SaljV. No.no^ I efteemyOu tobea very rational wian, and

lean

•len-

kfs

''^D I A L O G U E. L

do ask the queftionieriouQy i and therefore aniwer me

-i-- J . — ^ - - and if

afterwards you fliall thmk that I fpeak impertinently, I will be
content to l3e the fcnfelefs man : for he is much more a fool who
interrogates fimply, than he to whom the queftion is put.

S 1 M p L. If then you do not think me altogether limple, take
it for

granted that 1 have anlwered you already, and faid, that it
is impofllble, that one that is upon the Earth, as we are, fhould fee
by night that part of the Earth where it is day, namely, that is il-
luminated by the Sun.

^Sa l v. J^herefore you have never feen the Earth enlightned,
fave onely By ;day ^ but. yoii fee the Moon to fhine alfo in the
dead of night. And this is the caufe, tiimplicius^ which makes
yoii believe that the Earth doth not fiiine like the Moon ^ but if
you could fee the Earth illuminated, whilft you were in fome dark
place, like our night, you would fee it fliine brighter than the
Moon. Now if you defire that the comparifon may proceed
well, you muft' compare the light of the Earth, with that of the
Moon feen in the day time, and not with the fame by night : for
it is not in our power to fpe ^l^c Earth illuminated, fave oncly in
the day. Is it not To?

S I M p L. So it ought to be.

$ A i. V. And forafmuch as you your felf have already confefT-d
to have feen the Moon by day among fome little white Clouds
and very nearly, as to its afpc^, refembling one of them \ you did .
thereby grant, that thofe Clouds, which yet are Elementary
matters, are as apt to receive illumination, as the Moon , yea tiiamiKated
more, if you will but call to mind that you have fometimcs feen
fonie Clouds of vaft greatnefs, and as perfeft white as the Snow i
and there is no queftion, but that if fuch a Cloud could be con-
tmued lo lummous in the deep of night, it would illuminate the
places near about it, more than an hundred Moons. If therefore
we were affured that the Earth is illuminated by the Sun, like one
of thofe Clouds, it would be undubitable, but that it would be no
lefs fliining than the Moon. But of this there is no queftion to
be made, in regard we fee thofe very Clouds in the abfence of .
the Sun, to remain by night, as obfcure as the Earth : and that '
which is more, there is not any one of us, but hath *fecn n\any
timcsfome fuch Clouds low, and far off, and queftioncd whether
^hcy were Clouds or Mountains : an evident fign that the Moun-
tains arc no lefs luminous than thofe Clouds. a ^.iitUmi^^-
. ^AGrx. But what needs more difcourfe ? See yonder the Moon ^
lT2:c^"i ^^orethan half of it illuminated , fee thereth^t wall, 3:^;:/^
, T| ^^^^ fliineth \ retire a little this way, fo that you fee u[sxhantt:
he Moon fideways with the wall : look now ^ which of them
ihews more lucid > Do not you fee, that if there is any advantage,

K the

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

G. G A L 1 L i?: u s, bis'^ydeme.

the wall hath it ? The San fliineth on that wall , from thence it
rhethirdrefle. J, rcvcrbcrated upon the wall of the Hall, from thence its refle-
ZVl^ZeZ'n ^Icd upofl that chamber, fo that it falls on it at the third refleaion:
the firfl of t*r and I am very certain, that there is in that place more light, than
if the Moons light had direSly fahi upon it.

S i M p L. But this I cannot believe , for the illumination of the
Moon) efpecially when it is at the full, is very great.
Th light cfthi S^-^^- feemeth great by reafon of the circumjacent dark
Moon weaker than placcs j but abiolutcly it is not much;, and is lef^ than that of the
f^^'l/f twilight half an hour after the Sun.isfet^ which is manifcft, be-

caufe you fee not the fliadows of the bodies illuminated by the
Moon till then, to begin to be diftinguiflied on the Earth. Whe-
ther, again, that third refleaion upon that chamber, illuminates
iTiore than the firft of the Moon, may be known by going thether,
and reading a Book, and afterwards ftanding there in the night
by the Moons light, which will (hew by which of them lights one
may read more or lefs plainly, but I believe without further tryal
that one Ihould fee lefs diftinaiy by this later. '

S A L V. Now, SimplictHS^ (\i hapfy you be fatisfied^ you may
conceive, as you your felf know very well, that the Earth doth
fhine no lefs than the Moonj and the only remembring you of fomc
things, which you knew of your felf, and Icarn'd not of me, hath
affured you thereof : for 1 taught you not that the Moon (hews
lighter by night than by day, but you iinderftood it of your felfj
as alfo you could tell me that a little Cloud appearcth as lucid as
the Moon : you knew alfo, that the illumination of the Earth can-
not be fecn by night ; and in a word, you knew all this, without
knowing that you knew it. So that you have no reafon to be fcru-
pulous of granting, that the dark part of the Earth may illuminate
the dark part of the Moon, with no lefs a light than that where-
with the Moon illuminates the obfcurities of the night, yea rather
fo much the greater, inafmuch as the Earth is forty times bigger
than the Moon.

S I M p L. I muft confefs that I did believe, that that fecondar
, light had been the natural light of the Moon.

S A L V. And this alfo you know of your felf, and perceive
that you know it. Tell me, do not you know without teaching,
^■^^^y^^.^^ that the Moonlhews it felf mofe bright by night than by day, in
\hTbT.lh'ter refpea of the obfcurity of the fpace of the ambient > and confc-
«^/^:«r^r am- qucndy, do you not know i/i^ewer^, that every bright body fliews
the ckarer, by how much the ambient is obfcurer ?
S I >v ? L. This 1 know very well.

S A L V. When tl^ Moon is horned, and that fecondary light
fecmtthto you very bright, is it not ever nigh the Sun, and cou-
fcqucntly,in the light of crefnfcnlnm., (twilight ? J)

Simp

tHm noM bodiet
4t>pcdr
in dn
Hcnt,

I A L O G U £ IJ

'dark

the
ft,be-
>y the
Whe-
linates
iether,
night
ts one

may
t doth
>f fomc
h hath
I fliews
r felf i
icid as
th can-
'ithouc
e fcru-
[ninacc
ivherc-
rather

not

chingj
ay, in
nfc-
lews

^ light
con-

Sim PL. Itis fo j and I have oftentimes vvifti'd that the Air
would grow thicker, that I might be able to fee that fame light
more plainly i but it ever difappeared before dark night.

S A L V. You know then very certainly, that in the depth of
night, that light would be more confpicuous.

S I M p L. I do fo j and alfo more than that, if one could but
take away the great light of the crefcent illuminated by the Sun,
the pretence of which much obfcureth the other lefTer.

S A L V. Why, doth it not fometimes come to pafs, that one iiiay
in a very dark night fee the whole face of the Moon, without be-
ing at all illuminated by the Sun >

S I M p L. 1 know not whether this ever happeneth , fave onely
in the total Ecclipfes of the Moon.

Salv* Why, at that time this its light would appc^ir very
clears being in a moft obfcure medium^ and not darkned by the
clarity of the luminous crefcents : but in that pofition, how light
did it appear to you ?

S 1 M p L. 1 have fometimes feen it of the colour of brafs, and a
little whitifli j but at other times it hath been fo obfcure, that I

have wholly loft the fight of it.

S A L V. How then can that light be fo natural, which you fee fo
cleer in the clofe of the twilight, notwithftanding the impediment
of the great and contiguous fplendor of the crefcents j and which
again, in the more oblcure time of night, all other light removed,
appears not at all ?

S I M p L. I have heard of fome that believed that fame light to
be participated to thefe crefcents from the other Stars, and in par-
ticular from Vcnus^ the Moons neighbour.

S A L V. And this likewife is a vanity ; becaufe in the time of
Ks total obfcuration, it ought to appear more fliining than ever ^
lor you cannot fay, that the fliadow of the Earth intercepts the
fight of or the other Stars. But to fay true, it is not at

that inftant wholly deprived thereof, for that the Terreftrial He-
mifphere, which in that time looketh towards the Moon, is that
where it is night, that is, an intire privation of the light of the Sun.
And if you but diligently obferve, you will very fenfibly perceive,
that like as the Moon, when it is (harp-horned, doth give very little
light to the Earth j and according as in her the parts illumi-
nated by the Suns light do encreafe : fo likewife the fplendor to
our feeming encreafeth, which from her is reflefted towards us
thus the Moon, whilft it is fliarp- forked, and that by being between
*^^Sun and the Earthy it difcovereth a very great part of the Ter-
reltrialHemifphcre illuminated, appeareth very clear : anddepart-

inarmm *l o i ^ j i \^ anvi M^^i^ai*. Quadratures yon

^uuin the Sun, and pafllng towards the Quadrature , yo\x to underfiMnd
iee the faid light by degrees to grow dim i and after the ^'^^ ^^'^

K 1

Quadra- ltr9hicr$ cMem

^5 G. G A L I L ^ u s, his Syfteme.

auadrature, the fame appears very weak, becaufe it continuall
loieth toore and more ot the view of the liimuious part of the
Earth : and yet it fhould fucceed quite contrary, if that hght were
its owffe or communicated to it from the Stars v for then we (hould
fee it in the depth of night, and in fo very dark an ambient.

S 1 mip^'l. Stay a little i for I juft now remember, that I have
read irija Kttle modern traft, fall of many novelties " That this
" fecondary Hght is not derived from the Stars, nor innate in the
Moon, and leaft of all communicated by the Earth, but that it is
The feconUj " received from the' fame illumination of the Suii, which, the fub-
lightofthe Moon u ftance of the Lunar Globe being fomewhat tranlparcnf) pene-
cmfedhythe Sim tratetfa thorow all its body v but more hvclfly illuminateth the
"fuperficies of the Hemilphere. expoicd to the rays oi the Sun .
<^ and Jitdp/of"ttdity imbuing, and (as I may fay) iwallowing that
<^i licjlii!> after the manner of a cloud or clityftal, tranfimt^ic, and
cc rendecs it vifibly lucid. Afid this remember attght.) he

proveth by Authority, Experience ami Reafon ^ citing CkMudes^
!i< yitellidHyMacrohius^ and a ceita^in other modern- Author : and
^caddi0gf That it i^ leenby experience to {hinemoft:m- the days
ncareft the Conjunaion, that is, when it is horned, and is chicfty
bright abdat its liuib. And he farther writes, That in the Solar
jc Ecclipfes, when i^ is utider the Difcns of the Sun, it may be (een
cQ tranftucid, and mcMc efpeciaUy towards its utmoft Circle. And
fe invtb^'nafltFlaceyfor Arguments, as I think, he faith. That it not
'<c being able to derive that light either from the Earth, or from the
<»c Sta4?s^ oi? from it felf, it necefTarily follows, th^t it cometh from
it th<J Sdiii Betides that, if you do but grant this fuppofition, one
<■<- may eafily give convenient realons for all the particulars that
t<;0ami'. »'^FoPthe realbn why that fecundary light {hews more
t^lively towards the outmoftlimb, is, thefhortnefs of the fpac|
<t thai^the Suns rays hath to penetrate, in regard that of the lines
t« which pafs through a circle, thegreateft is chat whicbpaffetb
throagh. the centre, and of the reft, thofe which are fartheft from
it are always leis than thofe that are nearer. From the fame
« principle, he faith, may be (hewn why the faid light doth not
t^ much ditntniih. Andlaftly, by this way the caufe is affigned
whence it comes, that that fame nK>re fhining circle about the
utmoft edge of the Moon, is feen at the time of the Solar Ec-
cUpfe, in that part which lyeth juft under the Difcus of the Suri,
*^but rKM: ift that which is befide the Difcus : which happeneth
becaufe the rays of the Sun pafsdireftly to our eye, through the
^^parts^bf the Moon underneath : but as for the parts which arc
befides it, they fall beudes the eye .

S A L V. If this Philofopher had been the firft Author of this o-
piniojny I wottld not wonder that he (hould be fo a^edionate ta ift

1 A L O O li E.

5 more
t rpacj
le lines
paffeth
ft from
i€ fame
irfi not
(figned
mt the
4ar Ec-
lie Sun,
►peneth
4gh the
kh are

s o-
td it,

as to have received it for truth , but borrowing it from others, I
canriotfiiid any reaibn iufficientto excufe him for not pereeivino
its fallades ; and cfpecially after he had heard the true caufe of
that eftlct, and had it in his power to fatisfie himlelf by a thoufand
experiments, and manifeftcircumftanccs, that the fame proceeded
from the reflection of the Earth,arid from nothing elfe:and the more
this Ipcculation makes fomething to be dcfired, in the judgment of
this Author, and of aH thofe who give no credit to it ; fo much the
more doth, t^bcir not hjaving iinderftood and .remembred it^ excufe
^'^^^^ A^^" ^^^^^^ Ancients, who, I am very certain, did they now
underftaad it, would without the Icaft rcpughaaaiae admit thefeof
Andif I uwy freely tell you what I think , I cannot believe but
that this Mf^r/t'r/^ doth in his heart believe it ^ but I rather think^^
that the conceit he (hould not be the firft Author thereof , did a
ittle move him to endeavour to fuppreffe it dJ or to difparage it at
leaft amongfi: the limple , whbfe number we know to be very
great zr4 many there are , who much more affeft the nume-
rous applauds of the p?pple, idlAiLtheappiiob^tioa of fow. not
vulgar judgments, i^-r^ii r I • -* .j,, .:

S A G Hold good' S alvi^tm > for me thinks, I fee that yon
go not th^ vv^y to hit the true mark in this your difcourfc,for thefe
that '^coAfound all propriety , kuoWalfohow to make themfelves * r.nd.n i... .
Authors ot Others inventions , provided they be not fo ftale, teaUommuac.
and piiblick in the Schools and Market-places, that they are more
then notorious to every one. .

S A L V. Ha ! well aimed , you blame me for roving from the
pomt in liaiid ^ biu what. have yoU to do with Schools and Mar^
kets ? kit j^ot all c^Q.whether opinions and inventions be new to ^^^"'-^
men , or the men new to them'? If you ^contend about the e- tlt!lToT m!n
Iteem of the Founders^ of Sciences , which in all times do ftart up) *'sxv to opinions. ,
you may make your fejf their inventor , even to the Alphabet it * ^'"''fl''^' f^^^/
idf, and To gain admii^tion amongft that illiterate rabble ^ and Uctr^ranLrioa
though inproccfle of time your craft fliould be perceived, that
would bnt little piejudice your defignc for that others would
luccecd them m maintaining the number of your fautors but let
us return to prove to Simplicim the invalidity of the reafons of his
naodern Author , in which there are feveral falfities , inconfequen-
cies, and incredible Paradoxes. And firft, it is falfe that this fe- '7 he fnoriur^
condary light is clearer about the utmoft limb than in the middle ^'^^^

ParfQ r r • 111 appears lis for^»J

r lib 5 lo as to torm , as it were , a ring or circle more bright than ^ rhar t^'»
t^ft of its fpace or contence. True it is, indeed , that lookine ^''^ ' " t

— -i-i - - /- n 1 1 ** 5 extreme ctrcuni'^-'

on the Moon at the time of twilight , at firft fight there is the
leinblanr„ f...L • , . .° ii-.r.

verfityof confines that
tufedby meansof this

, . _ ^ ^ _ — ^ .-e- rexce ^ ..

^^nce of fuch a circle , but by an illtifion arifing from the di- '^'"^'^

and Kot^v
l.andrvh}-

bound the Moons Difcm , which are
fecondary light i forafmuch as on

con-
the part
towards

G. G A L 1 L ^ u S;, bis Sjfleme.

towards the Sun it is bounded by the lucid horns of the MoOd,
and on the other part, its confining term is the obfcure traft of the
twilight *, whofe relation makes us think the candor of the Moons
DijcHS to be fo much the clearer j the which happens to be ob-
fufcated in the oppolitc part , by the greater clarity of the cref-
cents ^ but if this modern Author had effaied to make an inter-
na wdy tc oh~ pofition betwecn the eye and the primary fplendor , by the ridg of
f ^^f^^ feme houfe , or fome other fcreen , fo as to have left vifible only
^iiolL " the grofeof the Moon 5 the horns excluded , he might have feefi
it all alike luminous.

Sim PI, I think, now I remember , that he writes of his
making ufe of fuch another Artifice 5 to hide from us the falfe
Incidum.

S A L V. Oh ! how is this (as I believed) inadvertency of his,
changed into a lie , bordering on rafhneffe for that every one
may frequently make proof of the contrary. That in the next
thi tMocMt Dif- place , at the Suns Eclipfe , the Moons Difcm is fccn otherwayes
%fceJiTffen ^^^^ P"vation , I much doubt , and fpccially when the E-
mtijbypivation. c\\^{t \s not total, as thofe muft necefTarily have been, which
were obferved by the Author \ but if alfo he fliould have difcove*
red fomewhat of light , this contradifis not , rather favoureth our
opinion '-y for that at fuch a time , the whole Terreftrial Hemi-
fphere illuminated by the Sun, isoppofite to the Moon, fo that
although the Moon^ fliadow doth obfcure a part thereof , y^t this
is very fmall in comparifon of that which remains illuminated.
That which he farther adds , that in this cafe , the part of the
^b , lying under the Sun , doth appear very lucid , but that
which lyeth befides it , not fo \ and that to proceed from the co-
ming of the folarrayes direftly through that part to the eye , but
not through this, is really one of thofe fopperies, which difco-
ver the other fiftions , of him which relates them : For if it be
requifite to the making a fccondary light vifible in the lunar D//-
CHS 5 that the raycs of the Sun came direSly through it to our
eyes , doth not this pitiful Philofopher perceive, that we (hould ne*
ver fee this fame fccondary light, faveonely at the Eclipfe of the
Sun ? And if a part onely of the Moon , far lefTe than half a de-
gree , by being remote from the Suns Dif ens , can defied or de-
viate the raycs of the Sun , fo that they arrive not at our eye ;
what (hall it do when it is dillant twenty or thirty degrees , as it is
at its firft apparition ? and what courfe fhall the rayes of the Sun
keep , which are to paffe thorow the body of the Moon , that
fke Author of the they may find out our eye ? This man doth go fucceffively confi-
t%i^Zdts^^'''^^^ that they may ferve his purpofe,

the things to his but doth not gradually proceed , accommodating his conceits to
I7fyat The ^^^^ ' ^^^"y ^^^y ^^^^ inftance , to make the light

w^s.

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

Dialogue I.

lie

the fubftancc of the Moon , he
is the tranfparcnce of a cioud.

ot the Sun capable to penetrate
makes her in part diaphanous, as

or cryftal : but 1 know not what he would think of fuch a tran-
fparency , in cafe the folar rayes were to paflea depth of clouds
of above two thoufand miles , but let it be fuppofed that he
fliould bbldly anfwer , that might well be in the Cccleftial, which
are quite other things from thefe our Elementary, impure, and
feculent bodies ^ and let us convift his error by luch waycs , as
admit him no reply, or Ctofay better) fubter-fuge. if he will
maintain , that the fubftance of the Moon is diaphanous , he
muft fay that it is fo , whileft that the rayes of the Sun are to pe-
netrate its whole profundity , that is , more than two thoufand
mks 5 but that if you oppofe unto them onely one mile , or
leffe, they (hould no more penetrate that, than they penetrate
one of our mountains.

S A G R. You put me in mind of a man , who would have fold ^ ^

rr. r I r 1 1 r ' r i T A jejt put Hponime

me a lecret now to correfpond, by means ot a certain iympathy ot ^/j^^ ^ouU fa a
magnetick needles , with one, that fliould be two or three thou- certatn fecret fcr
fand miles diftant h andl idling him , that I wouJd willingly buy tncjiiZtrJ^^
the fame , but that I defired firfl: to lee the experiment thereof, a thonfAnd mites
and that it did luffice me to make it , I being in one Chambcr,and
he in the next j he anfwered me, that in fo fmall a diftance one
could not lo well perceive the operation \ whereupon 1 turn'd him
going , telling him , that 1 had no mind, at that time ^ to take a
journey uiTto Grand Cairo , or to Mnfco^vy , to make the experi-
ment *, bur that, if he would go himfelf, I would perform the
other part, (laying in Venice, But let us hear whither the dedu-
ftion of our Author tendeth , and what neceffity there is, that he
muft grant the matter of the Moon to be moft perforable by the
rayes of the Sun , in a depth of two thoufand miles , but more
opacous than one of oUr mountains, in a thickneffe of one mile
oncly.

S A L V. The very mountains of the Moon themfelves are a
proof thereof, which perculTed on one fide of the Sun, do caft
on the contrary fide very dark fhadows , terminate, and more di-
ftinO: by much, than the (hadows of ours i but had thefe moun-
tains been diaphanous , we could never have come to the know-
ledg of any unevennetfe in the fuperficies of the Moon , nor have
feen thofe luminous montuofitiesdiftinguiflied by the terms which
%>arate the lucid parts from the dark : much leffe, (hould we fee
^b>s fame term lodiftinS , if it were true, that the Suns light did
Penetrate the whole thickneffe of the Moon \ yea rather, accord-
ing to the Authors own words , we (hould of neceffity difcern the
paffage , and continc, between the part of the Sun feen , and the
part not feen ^ to be very confufed , and mixt with light and

dark*

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2°K.B. 9,163

go G. G A L I L u s, his Syfieme.

darkneffe , for that that matter which admits the paffage of the
Suns rayes thorow a fpace of two thoiifand miies , muft needs be
fo tranfparent , that it would very weakly refift them ia, a hun-
dredth •> or leffer part of that thickneffe ^ nevertheleffe, the term
which feparateth the part illuminated from the obfcure , is inci-
dent 5 and as diftinft , as white is diftinft from black and e-
fpeciaily where the Seftion paffeth through the part of the Moon,
that is naturally more clear and montanous , but where the old
fpots do part 5 which are certain plains , that by means of their
fpherical inclination , receive the rayes of the Sun obliquely,
there the term is not fo diftinfi: , by reafou of the more dimme il-
lumination. That, laftly, which he faith , how that the fecondary
light doth not diminifli and languifh , according as the Moon en-
creafeth, but conferveth it felf continually in the fame efficacy^
is moftfalie, nay it is hardly feen in the quadrature, when, on
the contrary , it fliould appear more fplendid , and be vifible after
the crepHfcHlum in the dark of night. Let us conclude therefore,
that the Earths refleftion is very ftrong upon the Moon ; and that,
which you ought more to efteem , we may deduce from thence an-
other admirable congruity betwecn the Moon and Earth v name-
th Earthmay re- ly^ that if it be true , the Planets operate upon the Earth by their
^^roc^f^j^ i^otion ^igh^ > ^he Earth may probably be no leffe potent in

2ZZhi7ifJl operating reciprocally upon then> ^?fith the fame light , and perad-
venture, motion alfo- And though it fliould not move, yet may
it retain the fame operation h becaufe , as it hath been proved al-
ready 5 the aftion of the light is the felf fame , I mean of the light
of the Sun refle£i:ed j and motion doth nothing , fave only vary
theafpefts , which fall out in the fame manner , whether we make
the Earth move , and the Sun ftand ftill , or the contrary.

S I M p L. None of the Philoiophers are found to have faid, that
thefe inferiour bodies operate on the Coeleftial , nay, Arijiotlezi'
firmes the direa contrary.

S A L V- Ari^lotle and the reft , who knew not that the Earth and
Moon mutually illuminated each other , are to be excufed ^ but
they would juftly deferve our cenfure , if whileft they defire that
we fliould grant and believe with them , that the Moon operateth
upon the Earth with light , they fliould deny to us , who have
taught them that the Earth illuminates the Moon , the operation
the Earth hath on the Moon.

Si MPL. In fliort, I find in my felf a great unwiUingneffe to
admit this commerce , which you would perfwade me to be be-
twixt the Earth and Moon , placing it , as we fay , amongft the
number of the Stars for if there were nothing elfe , the great
feparation and diftance between it and the Ca-lefiial bodies , doth
in my opinion neceflarily conclude a vaft dlfparity between them.

eic ,

ii-

iry

cy,
on
ter

ne-
lieir
: in
•adr

but
that
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See Si}}jpl

ICIHS

I A LOG U

vvh;

-•rateafFeftion an

d radic

JjfiHit]! between
he Earth&MM»
in refpe^ of thttr

Solidity of tht

inveter

ted opinion can do , fince it is fo powerful , that it makes you think
that thole very things favour you , which you produce againft
your felf. For if feparation and diftance are accidents fufficient to
perfwade with you a great diverfity of natures, it mviii follow that
proximity and contiguity import fimilitude. Now how much more
ncerer is the Moon to the Earth, than to any other 6f the Cdclcftial
Orbs? You muft acknowledg therefore,according to your own con-
ceffion (and you (hall have other Philofophers bear you company)
that there is a very great affinity betwixt the Earth and Moon.
Now let us proceed, and fee whether any thing remains to be con
fidered, touching thofe objeftions which you made againft the rq^
Icmblances that are between thefe two bodies.

S 1 M p L. It refts, that we fay fomething touching the folidity ot
the Moon 5 which 1 argued from its being exquifite fmooth and
polite , and you from its montuofity. There is another fcruple al-
fo comes into my mind , from an opinion which 1 have , that the
Seas refle&on ought by the equality of its furface, to be rendered
llronger than that of the Earth , whole fuperficies is fo rough and

opacous. . r , 1.1 1

S A L V. As to the firft objefiion j I fay, that like as among the

parts of the Earth, which all by their gravity ftrive to approach the
neareft they can poffible to the center , fome of them alwayes are i««4r^/p^^^
more remote from it than the reft, as the mountains more than ""-^
the valleys, and that by reafon of their folidity and firmneffe
(for if they were of fluid, they would be even) fo the feeing fomc
parts of the Moon to be elevated above the fphericity of the lo\fr-
cr parts , argucth their hardnelTe ^ for it is probable that the mat;^
ter of the Moon is reduced into a fpherical form by the harmoni-
ous confplration of all its parts to the fame fentenfe. Touching
the fecond doubt , my thinks that the particulars already obferved
to happen in the Looking-glaffes, may very well affure us,that the
refleftion of light comming from the Sea , is far weaker than that rbg Seas reflet
which Cometh from Land underftanding it alwayes of the ^'^^^fj'^^^^^^
univcrfal reflexion ^ for as to that particular , on which the wa- ^^^^^E^rrT ^
ter being calm , cafteth upon a determinate place , there is no
doubt, butthathewhofhall ftand in that place , fliallfeea very
gteat rcfleaion in the water , but every way elfe he ftall lee the
furfacc of the Water more obfcure than that of the Land and to An^cxpm^^^^
prove it to yourfenfes, let us go into yonder Hall, and power ^allZythem'tr
forth a little water upon the Pavement. Tell me now, doth not ufc cu^r tb^'>
this Wet brick fhew more dull than the other dry ones ? Doubt- '^""'f'^' '
leffe it doth , and will fo appear , from wrhat place foever you be-
hold it, except one onely , and this is that way which the light
Cometh , that entcrcth in at yonder window ^ go backwards

ore by a little and a little.

S 1 M? I.

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8 1 G. G A L 1 L ^ u S;, bis Sj[!eme.

S I M p L. Here 1 fee the weft part fliine more than all the reft of
the pavtment , and 1 fee that it fo hapncth , becaufc the refle-
xion of the light which entereth in at the window , conieth to-
wards me.

S A L V. That moifturc hath done no more but filled thofe little
cavities which are in the brick with water , and reduced its fuper-
ficies to an exaft eveneffe ^ whereupon the reflex rayes ifluc
unitedly towards one and the fame place , but the reft of the
pavement which is dry , hath its protuberances, that is an innu-
snerable variety of inclinations in its fmalleft particles *, whereup-
on the rcfleflions of the light fcatter towards all parts, but more
weakly than if they had gone all united together ^ and therefore,
the fame flieweth almoft all alike , beheld feveral wayes , but far
lefle clear than the moiftned brick. I conclude therefore, that the
furfaceof the Sea , beheld from the Moon , in like manner as it
would appear moft equal, (the Iflands and Rocks deduXcd) fo it
would fliew kSc clear than that of the Earth , which is montanous
and uneven. And but that I would not feem , as the fayinc^ is,
to harp too much on one ftring, I could tell you that 1 have ob'
ferved in the Moon that fecondary light which I told you came to
her from the reflefiion of the Terreftrial Globe , to be notably
The fecondary motc dear two or three dayes before the conjunaion , than after,
iightof the Moon that Is , when \ve fee it before break of day in the Eaft than
when it is feen at night after Sun-fet in the Weft , of which dif-
^fttr. ference the caule is , that the Terreftrial Hemifphere , which looks

towards the Eaftern Moon, hath little Sea , and much Land to
wit, all whereas, when it is in the Weft , it beholds very

great Seas , that is, the whole Atlantich^ Ocean as far as America-
An Argument fufficiently probable that the furface of the water
appears leffe fplendid than that of the Earth.

S I M p i. So that perhaps you believe , thofe great fpots difco.
vered in the face of the Moon , to be Seas , and the other clearer^
parts to be Land , or fome fuch thing ?

Salv. This which you ask me, is the beginning of thofe in-
congruities which I efteem to be between the Moon and the
Earth, out of which it is time to dif-ingage our felves, for wc
have ftayed too long in the Moon. I fay therefore , that if there
were in nature but one way onely, to make two fuperficies illuftra-
ted by the Sun , to appear one more clear than the other , and
that this were by the being of the one Earth , and the other Wa-
ter s it would be necelTary to fay that the furface of the Moon
were part earthy and part aquatick h but becaufe we know many
wayes to produce the fame efteft (and others there may be which
we know not of ^ ) therefore I dare not affirm the Moon to con-
fift of one thing more than, another : It hath been feen already

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tan
lif-

ter

Dialogue. L 85

that a filvei'plaic boiled 5 being toucht with the Burnidier , be-
cometh of white obfcure , that the moift part of the Earth (hews
more obfcure than the dry , that in the tops of Hills , the woody-
parts appear more gloomy than the naked and barren 5 which
hapneth bccaule there falleth very much fliadow among the Trees,
but the open places are illuminated all over by the Sun. And this
mixtion of fliadow hath fuch operation , that in tufted velvet, the
filk which is cut , is of a far darker colour than that which is not
cut, by means of the fliadows diifufed betwixt thred and thred,
and a plain velvet fliews much blacker than a Taffata, made of the
fame filk. So that if there were in the Moon things which fliould
look like great Woods , their afpeft might reprefent unto us the
Ipots which we difcover j alike difference would be occafioned, if
there Wer6 Seas in her : and laftly, nothing hindreth? but that thofe
fpots may really be of an obfcurer colour than the reft j for thus
the fnow makes the mountains fliew brighter. That which is plain- 7 he obfcurer
lyobferved in the Moon is, that its moft obfcure parts are all P^^^^^^^^^^^
plains 5 with few rifes and bancks in them ^ though fome there be, rnore hi^ht mjum-
the reft which is of a brighter colour , is all full of rocks, moun- t^i^oHs.
tains, hillocks of fphcrical and other figures^ and in particular,round
about the fpors are very great ledges of mountains. That the Long uAges of
fpots be plain fiiperficies , we have affuredproof , in that we fee, cf7he
how that the term which diftinguiftieth the part ilhiminated from ^r^^ij^.
the obfcure 3 in croffing the fpots makes the interfeftion even , but
in the clear parts it fliews all craggy and fliaggcd. But I know not
as yet whether this evenneffe of fuperficies may be fufficient of it
felf alone , to make the obfcurity appear , and I rather think not.
Befides, I account the Moon exceeding different from the Earth ^
for although 1 imagine to my felf that thofe are not idle and dead
Regions , yet I affirm not , that there are in them motion and life, ^^^'^'^^
much lefs that there are bred plants, animals or other things like ^AiZTthinli hks
to ours \ but, if fuch there be, they fliould neverthelefs be vel-y xo cur, , ^bm if
different, and remote from our imagination. And I am induced fo '^^^i^/'^ Thl/Zl
to think, becaufe in the firft place, I efteemthat the matter of the very dijcrent.
Lunar Globe confifts not of Earth and Water \ and this alone
fufficeth; to take away the generations and alterations refembling
purs : but now fuppofing that there were in the Moon, Water and J*^'
Earth, yet .would they not produce plants 'and animals like to "^7£L^{
ours \ and this for two principal reafons : The firft is, that unto our ^ Thole ^fpctti of
Produaions there are required fo many variable afpefts of the Sun, f;;
that without them they would all mifcarry •* i^^w the habitudes of ons, Aremt >

Sun towards the Earth are far different from thofe towards
the Moon. We as to the diurnal illumination, have, in the greater
part of the Earth, every twenty four hours part day, and part
night, which effcft in the Moon is monethly : and that annual decU-

2 pation

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a G

A Ll Lit us

bis Sjfli

NatuYAi lii»s '^^tion and elevation of the Sun in the Zodiack, by which it pro-
intheMooii ^r;^ ^/ diiccth diveifity of Scaions, and inequahty of dayes and nights,
'^t'Tj^^ finifhed in the Moon in a moneth , and whereas the Sun to us
th shh afecndetl rifcth and declineth fo much, that from the grcateft to the leaft al-
anddesiireth wnh^ xitwA^^ there IS a difference of almoft 47 degrees, for fo much is
'degrZTandto\Z thc diftance from (5ne to the other Tropick^ this is in the Moon
Earthof forty fe- but ten degrees only, or little more ; namely, as much as the grea-
ve» grees. Latitudes of the Dragon on each fide the Ecliptick. Now

confider what effeS the Sun would have in the torrid Zone, fhould
it continually for fifteen daycs together beam forth its Rayes upon
it ^ which without all queftion would deftroy plants , herbs,
and living creatures : and if it fliould.chance that there were any
produftion, it would be of herbs, plants, and creatures very diffe*
There dre r.o rent from thofe which are now there. Secondly, I verily believe
TAinsintheMooH. that in the Moon there are no rains , for if Clouds fliould gather
in any part thereof, as they do about the Earth, they would there-
upon hide from our fight fome of thofe things , which we with the
Te/e/ct?pe behold in the Moon, and in a word, would fome way or
other change its fhjenomenon-idin cfFed which I could never by long
and diligent obfervations difcover ^ but alwayes beheld it ka a
even and purg ferenity.

S A G R. To this may be anfwered , either that there might be
great mifts, or that it might rain in the time of their night, that ii,
when the Sun doth not illuminate it.

S A v: If other paflages did but affureus, that there were ge-
nerations in it like to ours, and that there was onely wanting the
concourfeof rains', we might find ouf this, or fome other temper-
rament to ferve inftead thereof, as it happens in Egyp by the int.
undation of hile : but not meeting with any accident, which cor*
refponds with ours,of many that have been fought out for the pro-
duftion of the like efFe&, we need not trouble our felves to intro-
duce one alone j and that alfo, not becaule we have certain obfer"*
vation of it, but for a bare non- repugnance that we find therein.
Moreover, if I was demanded what my firft apprehenfion, and pure
natural reafon dilated to me concerning the produflion of things
like or unlike there above, I would alwayes reply ^ that they are
xnoft different, and to us altogether unimaginable, for fo me thinks
the riches of Nature-, and the omnipotence of our Creator zmi
Goverr^our, do require.

Sagr. 1 ever accounted extraordinary madneffe that o£ thofc,
who would make humane comprehenfioa the meafure of what na-
The hnvhi^ *^^ ^^th a powpr c^r knowledge to effeft^ whereas on the coh-
perfta kj'or^ied^. ^^^^J" ^ny the leafl: efifefi in Nature, which can be fiiMy

fome b
Hnderfland
things.

p m^Kf iinderltood by the moft fpeculative wits in the world. This their
tnT .u preiumption of knowing aJI,

can take beginning from no-
thing

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2°K.B. 9,163

I A I O G U E

thing, unleflcfroiU their never having known any thing ; for if
one hath but once onely experienced the perfeft knowledg of one
onely thing , and but truly taftcd what it is to know , he (hall per-
ceive that of infinite other conckifions, he underftands not fo much
as one.

S A L V. Your di{courfe is very concluding ^ in confirmation of
which we have the example of thofe who underftand , or have
known fame thing , which the more knowing they are, the more
they know 5 and freely cohfeffe that they know little *, nay, the
wifeft man in all Greece , and for fuch pronounced by the Oracle,
openly profeffed to know that he knew nothing.

S I M p L. It muft be granted therefore, either that Socrates or
that the Oracle it felf was a lyar , that declaring him to be mofl
T^ife, and he confeffing that he h^ewp himfelf to he moft ig-
norant.

S A L V. Neither one nor the other doth follow , for that both ^^J'^'^^"/^'^^
xheaflertionsmay be true. The Oracle adjudged Socrates the ^i- 'socrates
feft of all men , whofe knowledg is limited j Socrates acknow- the wfifi of his
ledgeth that he knew nothing i» relation to abfolutc wifdome,
which is infinite ^ becaufe of infinite , much is the fame part,
as is little , and as is nothing (for to arrive c/. g. to the infinite
number , it is all one to accumulate thoufands, tens, or ciphers^)
therefore Socrates w^U perceived his wifdom to be nothing, in
comparifon of the infinite knowledg which he wanted. But yet,
becaufe there is Come knowledg found amongft men , and this
iu>t equally ftiarcd to aU , Socrates might have a greater fharc
thereof than others ^ and therefore verified the anfwer of the
Oracle.

Sag r, 1 think I very well uttderftand this particular amongft
men , Simflictus there i§ a power of operating , but not equally
^ifpenfed to all j aixlit is without qucftion , that the power of an
Emperor is far greater tlian that of a ptivate perfon j but, both
this and that are nothing in comparifon of the Divine Omnipo-
tence. Atiiimigft men , there are fome that better underftand
AgticulttiFi^ than many others ^ but the knowledg of planting a
Vine in a trench , what hath it to do with the kncwledg of ma-
•king it to fprout forth^ , to attraft nourifliment , to leleft this good
part from that other, for to make t4iereof leaves , another to make
fprouts , another to make grapes , another to make raifins , ano-
<iherto make the huskes oi them, which are the works of moft
^ Nature ? This is one only particular aft of the innumerable,
Vvhrch Nature doth and in it alone is difcovered an infinite wif- Divine mfdom
fomy fo that Divine Wifdom may be concluded to be infinitely i^fi^nd; infinite.
infinite.

S A L V. Take hereof another exaniple. Do we not fay that the

)udi«

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.86 G. G A L 1 L it u his Syfleme.

judicious difcovering of a moft lovely Statnam^k piece of Marble,
Buonamiotri, ^ ]^^^^ fublimatcd the wit of Bmnarruotti far above the vulgar wits
^^ll%miUy'^''' of Other men > And yet this work is onely the imitation of a
meer aptitude and difpofition of exteriour and fuperficial mem-
bers of an immoveable man j but what is it in comparifon of a
man made by nature, compofed of as many exteriour andinte-
riour members , of fo many mufcles, tendons , nerves , bones,
which ferve to fo many and fundry motions ^ but what fliall we
fay of the fenfes , and of the powers of the foul , and laftly, of
the underftanding > May we not fay 5 and that with teafon, that
the ftruSure of a Statue fals far fliort of the formation of a living
man , yea more of a contemptible worm ?

S A G R. And what difference think you , was there betwixt the
Dove of Arcbitas^ and one made by Nature ?

S I M p L. Either I am none of thefe knowing men , or elfe
there is a manifeft contradiction in this your difcourfe. You ac-
cCHint underftanding amongft the greateft (if you make it not the
chif f of the) hncomiums afcribed to man made by Nature , and
a little before you faid with Socrates^t\i^t he had no knowledg at
alii therefore youmuft fay, that neither did Nature underftand
how to make an underftanding that underftandeth.

Salv. You argue very cunningly, but to reply to your objc-
aion I muft have recourfe to a Philofophical diftinSion, and fay
jLfi i- that the underftanding is to be taken too ways, that is intenfi^e^ or
thVry J/tfTn" extenfii^e h and that extenfi^e, that is,as to the multitude of intel-
tenrive, ^*r/'«/« ligibles, which are infinite, the underftanding of man is as no-
cxtenfive. thing, though he fliould underftand a thoufand propofitions j for
that a thoufand, in refpeft of infinity is but as a cypher: but taking
the underftanding intenfi've^ (in as much as that term imports ) in-
tenrivcly,that is,perfeaiy fome propofitions,! fay, that humane wif-
dom underftandeth fome propofitions fo perfeftly, and is asabfo-
lutely certain thereof, as Nature herfelf j and fuch are the pure
Mathematical (ciences, to wit. Geometry and Arithmetick: in which
Divine Wifdom knows infinite more propofitions,becaufe it knows
themall*, but I believe that the knowledge of thofe few compre-
hended by humane underftanding, equalleth the divine, as to the
certainty objeiii'i^e^ for that it aniveth to comprehend the necef-
fity thereof, than which there can be no greater certainty.

S I M p 1 his feemeth to me a very bold and rafli expreffion.
Salv Thefe are common notions, and far from all umbrage

temerity, or boldnefs, and detraft not in the leaft from the Ma-
jefty of divine wifdom 5 as it nothing diminiflieth the omnipotence
thereof to fay^ that God cannot make what is once done, to be un-
done : but I doubt, /,that your fcruple arifeth from an o-
pinion you have, that my vvords are foniiswhat equivocal j there-
fore

Dialogue!. ^7

iDi-e the better toexprcis my fclf I lay, that as to the truth, of
which Matheuutlcal demonftrations give us the knowledge, it is
the i-cimc, which, the divine wifdom knoweth , but this I muft grant
YOU, that the manner whereby God knoweth the infmice propo- G-'ds ma>,iu^rof

■ ^ r i 1 > 1 r r -I'll \\ 4. k:"'^'^'^ differer.c

lirions, of which we underltand lome few, is highly more excellent f^^^ ^^^^

than ours,which proceedeth by ratiocination>and palleth trom con-

clufion to conclulion * whereas his is done at one tingle thought or f/.^^^;;^,, J/ ^

intuitions and whereas we , for example, to attain the knowledg

of fome pafllon of the Circle , which hath infinite , beginning

from one of the moft fimple , and taking that for its definition,

do proceed with argumentation to another y and from that to a

thiid , and then to a fourth, &c. the Divine Wiidom , by the

apprelienfion of its elfeiice comprehends, without temporary raci-

ocination , all thefe infinite patfions which notwithllandmg,are

in effeS: virtually comprifed in the definitions of al! thingsj and, to pefinitiom com-

conclude ,as being infinite, perhaps are but one alone in their nature, ^^^^'J pl'^[lf!f ,1,

and m the Divine Mind ^ the which neither is wholly unknown to thwisrs defined,

humane underftandins^ , but onely be-clouded with tJ«ck i^^d J"^;;',^^^^^^

groffe miftss which co«^ i« P^*-^ ^« be diOlpatcd and clarified,

when we are nr^<^ Matters ot any conclufions , hriiily demon-

ftratcd , and fo perfeftly made ours , as that we can fpeedily run

through them ; for in fum , what other, is that propofition, that

the fquare of the fide fubtending the right angle in any triangle,

is equal to tlie fquares of the other two , which include it , but

onely the Paralellograms being upon common bafes , and between

parallels equal amongft themi'elves ? and this, laftly, is it not the

fame , as.to fay that thole two fuperficies are equal , of which

equal parts applyed to equal parts , poffcfTe equal place ? Now The difiottrfu

thefe inferences, which our intelleft apprehendeth with time and a -^J^ ^^g;'^^

gradual motion 5 the Divine Wifdom , like light , penetratcth in

certain time , the

aninftant, which i^the fame as to fay , hath them alwayes P^'^' ^;^;;;^f7^^;
fent : I conclude therefore , that our underftanding ^^^^^ ^ent- thlttMh
the manner and the multitude of the things comprehended by Ms^thry^ai^ajes fre-
is infinitely furpaft by the Divine Wifdom', but yet I do notfo^"'''*
vilifie it , as to repute it abfolutely nothing *, yea rather, vvhen I
confider how many and how great mifteries men have underftood,
diCcovercd, and contrived , 1 very plainly know and underftand
the mind of man to be one of the works, yea one of the molt ex-
cellent works of God. r ir •

S A G R. 1 have oft times confidered with my felt i in purfuaace rhe Wnof mAn
of that which you fpeakof , how great the wit of man is and ^^rn.rMj.cuu.
whirft 1 r^^n thorow fuch and fo many admirable inventions found
out by him , as well in the Arts, as Sciences *, and again rcfiefling
upon my own wit , fo far from promifing me the difcovery of any
^hingnew, that I dcfpair of comprehending what is already -dif-

eovered,^

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

gg G. G A L I L u s, his Syjleme.

covered , confounded with wonder , and furprifed witli defpera-
tion I account my lelf little leffe than miferable. if I behold a
Statue of fome excellent Mafter , I fay with my fclf i When wilt
thou know how to chizzle away the refufe of a piece of Marble,
and difcover fo lovely a figure , as lyeth hid therein ? When wilt
thou mix andfpreadfo many different colours upon a Cloth , or
Wall, andreprefent therewith all vifiblc objeits, like z Michael
Angela , a Raphaello, or a ri'x.varjo ? If I behold what inventions
men have in comparting Mufical intervals , in eftablifliing Pre-
cepts and Rules for the management thereof with admirable de-
light to the ear : When fliall I ceafe my aftoniftiment ? What
(hall I fay of fuch and fo various Inftruments of that Art > The
reading of excellent Poets, with what admiration doth it fwell
any one that attentively confidereth the invention of conceits,
and their explanation ? What (hall we fay of Architefturc ?
r^, • ■ r What of Navigation ? But, above all other ftupendious invcnti-
writingUHfendhu, ons , what fubUmity of mmd was that m mm , that imagmcd to
nhvtMii ethers. (^jj^fg]f g^d out a Way to communicate his moft fecret thoughts
to any other perfon , though very far diftant from him cither in
time, or place , fpeaking with thofc that are in the India s j fpeak-
ingtothofe that are not yet born , nor fliall be this thoufand, or
ten thoufand years > and with how much facility > but by the va^
*Forcffot*anyriou5 collocation of * twenty little letters upon a paper ? Let this
only the Italian ^ the Seal of all the admirable inventions ot man , andtkeclofe
Alphabet ^onfitts. our Difcourfe for this day : For the warmer hours being paft,
1 fuppofe that Salviatus hath a defire to go and take the air in his
Gondelo *, but too morrow we will both wait upon you , to con-
tinue the Difcourfes we have begun, &c.

G A L I L U S

Galileos Lyncseus,

S \ STEME

O F THE

WORLD.

The Second Dialogue.

INtEKLOCVroKS.
Salviatus, Sagredus, andSiMPLieius.

Ic yeftcr-daycs diverfions wluch led us
out of the path of our principal difcourfe,
were fuch and fo many , that I know not
how I can without your afllftance reco-
ver the track in which I am to proceed.

S A G R. I wonder not , that you , who
have your fancy charged and laden with
both what hath been , and is to be fpo-
ken , do find your felf in fome confufi-
' but I , who as being onely an Auditor , have nothing to bur-
then my memory withal , but fuch things as I have heard, may
haply by a fuccindl rehearfal of them , recover the firft thred
of our Difcourfe. As far therefore as my memory fcrves me , the
fum of yefter-dayes conferences were an examination of the Prin-

M «ples

G. G A L I L ^ u s, his Sy^en:e.

ciplesof ttolomy 2tnd Copernicus and which of their opinions is
the more probable and rational ^ that, which aflSrmeth the fub-
ftance of the Coelcftial bodies to be ingenerable, incorruptible, un-
alterable, impa{lible,and in a word^exempt from all kind of change,
fave that of local, and therefore to be a jifth effencc^ quire different
fromthisof our Elementarybodics , which are generable , corrup-
tible, alterable, &c. orelfe the other , which taking away fuch
deformity from the parts of the World , holdeth the Earth to en-
joy the fame perfedions as the other integral bodies of the uni-
verfe i and cfteemeth it a moveable amd erratick Globe , no leffe
than the Moon, Jupiter^ Vcnus^ or any other Planet : And laftjy,
riuketh many particulM parallels betwixt the Earth and Moon j
and more with the Moon, than with any other Planet \ hap-
ly by reafon we have greater and more certain notice of it , as
being lelTe diftant from us. And having, laftly , concluded this
fecond opinion to have more of probability with it than the firft,
I fliould thii\k it beft in the fubfequent diicourfes to begin to exa-
mine whether the Earth be efteemcd immoveable , as it hath
been till now believed by moft men , or elfe moveable , as fomc
ancient Phtlofopbers held , and others of not very receffe times,
were of opinion h and if it be moveable , to enquire of what
kind its motion may be?

S A L V. I fee already what way I am to take j but before we
offer to proceed any farther , I am to fay fomething to you touch-
ing thofe laft words which you fpake, how that the opinion which
holds the Earth to be endued with the fame conditions that the
Caleftial bodies enjoy , feems to be more true than the contra-
ry j for that I affirmed no fuch thing , nor would 1 have any of the
Fropofirions in controverfie , be made to fpeak to any definitive
fenfe : but I onely intended to produce on either part , thofe rea-
fons and anfwers, arguments and folutions , which have been hi-
therto thought upon by others , together with certain others ,
which I have ftumbled upon in my long fearching thereinto , al-
wayc« remitting the decifion thereof to the judgment of others.

S A a 1^ I unawares tranfported by my own fenfe of the
thing > and believing that others ought to judg as I did , I made
that CQiiclufion univerfal, which fliould have been particular j and
therefore confelTe 1 have erred , and the rather , in that I know
not what Simplicif*s his judgment is in this particular.

S I M p L. 1 muft confefTe , that I have been ruminating all this
night of what paft yefterday , and to fay the truth , I meet there-
in with many acute, new, aud plaufiblc notions j yet neverthelefs,
I find my felf over-perfwaded by the authority of fo many great

Witters and in particular ~ €^^- I fee you fliake your

head Sagredus^ and fmile to your felf, as if I had uttered fome
great abfurdity. S a c a*

D I A L C G U F. L 91

. S A G R. I not onely Imile , but to tell you true ? am ready to
burll with holding in my felf from laughing outright , for you
have put mc in mind of a very pretty paffage , that I was a wic-
nefie of 5 not many years lince , together with I'ome others of
my worthy friends , which I could yet name unto you.

S A L V. Ic would be well that you told us what it was , that fo
Simf Ileitis may not ftill think that he gave you the occafion. of
laughter. *

S A G R. I am content. I found one day, at home in his houfe, at
Venice , a flimous Phifician, to whom fome flockt for their ftudies,
and others out of curiofityjfometimes came thither to fee certain A-
natomies diifeded by the hand of a no lefle learned, than careful
and experienced Anatomift. It chanced upon that day, when I was
there, that he was in fearch of the original and rife of the Nerves, '^^^^
about which there is a famous contioverfie between the Gahnifis Ue , a»,ddccordiMi
and FerifatQticky-) and the Anatomift {hewing, how that the great i'hijieiAHS.
number of Nerves departing from the Brain > as their root , and
pafling by the nape of the Neck, diftend rhemfelves afterwards
along by the Back-bone , and branch thcmfelves thorow all the
Body ; and that a very fmall filament , as fine as a thred went to
the Heart ^ he turned to a Gentlenian whom he knew to be a Fe-
ripatctick^ Philofopher , and for whofe fake he had with extraor-
dinary exafinefle, difcovered and proved every thing, and demand-
ed of him, if he was at length fatisfied and perfwaded that the origi-
nal of the Nerves proceeded from the Brain, and not from the
Heart ? To which the Philofopher , after he had ftood mufing a

7'be oriffina! of
hf Nsrv s ac
corAir.g to AriOq-

while , ; anfwered i you have made me to fee this bufineffe fo ^«/«"''''/^

The ridicftloM

piainly aod fenfibly , that did not the Text of Ariflotle aiTert the ^nt[thc ori^l'Ii 4
contrary , which pofitively affirmeth the Nerves to proceed from Nerves.
the Heart , I fliould be conftrained to confefTe your opinion to be
true. .v;;i id ii^nod] c c ^.i v

S I M p L. I would>have^ you kttdw myMafters , that this contro-
verfie about the original, of the Nerves is not yet io proved and
decided , as fome may perhaps perfwade themfelves.
, S A G R. Norqueftionleffe ever fliall it be , if it find fuch like
eontradidQrs j but that which you fay , doth not at all lefTen the
extravagance of the anfwer of that Peripatetick, , who againft
fuch fenfible experience produced not other experiments , or rea-
sons o f ^Arijiotle , but his bare authority and pure ipfe dixit,
^^Si m Vl- Ariftotle had not gained fo great authority , but for
*e force of his Demonftrations , and the profoundneffe of his
aigunaex^ts ; but it ii requifite that we underftand him , and not
Qnely underftand him , but have fo great familiarity with his
ftpoks , that we form a perfefirW^^^ thereof in our minds , fo as
that every laying of his may be alwayes as it were, prefcHt in out

M 2 mC'

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2°K.B. 9,163

%ecjuifitesto fit:
a man to philof}-
phate vfcll after
the manner of A-
rirtode.

' A cunn'tKg way
to g.nher Thilofo-
phf out of any ktok^
yphatfoever.
* A word fignify-
ing works compo-
fcd of many frag-
ments of verfcs
collcclot out of the
Poets.

Invetitionof the
Telefcope taken
from Ariflodc.

G, G A L 1 L ^ u his Sylleme.

memory for he did not write to the vulgar , nor is he obliged to
Ipinouthis Sillogilmes with the trivial method of difputes ; nay
rather , ufing a fieedome > he hath fometimes placed the proof
of one Propofition amongft Texts , which feem t.o treat of quite
another point , and therefore it is requifite to be matter of all
that vaft Idea , and to learn how to conned this pafTage with that,
and to combine this Text with another far remote from it j for it
is not to be qucftioned but that he who hath thus ftudied him ,
knows how to gather from his Books the demonftrations of every
knowable deduSion , for that they contein all things.

S A G R. But good Simplicius , like as the things fcattered here
and there in Arifiotlc , give you no trouble in coUefiing them,
but that you perfwade your felf to be able by comparing and
conne£i:ing fcveral fmall fcntences to extraft thence the juice of
fome defired conclufion , fo this , which you and other egregi-
ous Philofophers do with the Text of Ariftotle , I could do by the
verfes of Virgil , or of O^id , compofing thereof * Centones, and
therewith explaining all the affairs of men , and fecrets of Na-
ture. But what talk I of Virgil^ or any other Poet ? I have a lit-
tle Book much fliorter than Arijlotle and Omd^ in which are con-
teined all the Sciences, and with very little ftudy, one naay gather
out of it a moft pcrfefi Idea , and this is the Alphabet ; and there
is no doubt but that he who knows how to couple anddifpofe
aright this and that vowel , with thofe, or thofe other confonant^,
may gather thence the infallible anfwers to all doubts , and de-
duce from them the principles of all Sciences and Arts , juft in the
fame manner as the Painter from divers fimple colours , laid feve-
rally upon his f^//^^^ , proceedethby mixing a little of thisand
a little of that , with a little of a third , to reprefent to the life
men, plants, buildings, birds, fiflies, and in a word, counterfeit-
ing what ever objeft is vifible , though there be not on the Pallate
all the while, either eyes, or feathers, or fins, or leaves, orftones.
Nay, farther, it is neceffary , that none of the things to be imita-
ted , or any part of them , be aftually among colours , if you
would be able therewith to reprefent all things^ for fliould there
be amongft them 'Z/. gr. feathers ^ thefe would fervc to reprefent
nothing fave birds , and plumed creatures.

S A L V. And there are certain Gentlemen yet living,and in health,
who were prefent, when a Dofior , that was Profeffor in a fa-
mous Academy , hearing the defcription of the Telefcope , by him
not leen as then , faid, that the invention was taken from yiri-
Jiotle^ and caufing his works to befetch't, he turned to a place
where the Philofopher gives the reafon , whence it commeth , that,
from the bottom of a very deep Well , one may fee the ftars in
Heaven , at noon day ^ and, addreffing himfelf to the company,

fee

1 A O G U E

II.

fee here, faith he, the Well , which reprefenteth the Tube , fee
here the grofs vapours , from whence is taken the invention of
9JLl ^'^^ Cryftais , and fee here laftly the fight fortified by the palfage
of the rays through a diaphanous , but more denfe and obfcure

S A G R. This is a way to comprehend all things knowable, much
like to that wherewith a piece of marble conteineth in it one, yea,
a thoufand very beautiful Statua^s , but the difficulty lieth in be-
ing able to difcover them ^ or we may fay , that it is lik^ to the
prophcfies of Abbot Joachim , or the anfwers of the Heathen
Oracles , which are not to be underftood , till after the things
fore-told are come to paffe.

S A L V. And why do you not adde the prediftions of the Ge^
^ethliacks , which are with like cleerneffe feen after the event , in
their Horofcopes , or, if you will, Configurations of the Heavens-

S A G R. In this manner the Cliymifts find , being led by their
melancholly humour , that all the fublimeft wits of the World
have writ of nothing elfe in reality , than of the way to make
Gold j but, that they naight tranfmit the fecret to pofterity with-
out difcovering it to the vulgar > they contrived fome one way, and
Come another how to conceal the fame under feveral maskes *, and
it would make one merry to hear their comments upon the ancient
finding out the important mifteries , which lie hid under
^hcir Fables ^ and the fignification of the Loves of the Moaa,
and herdcfcending to the Earth for Endimion ; her difpleafure
againft ASiean , and what was meant hy Jupiters turning himfelf
int<;> a fliowrc of Gald ', and into fbmes of fit^ ^ and what ^reat
lecrets of Art arc QCfcnCeined in that Mercury the InterfreUr:, in
Ihofe thefts of fUtto^y and in thofc Brjwcfcex of Ga/rf.

S I M p I believe, and in part know,that there want not in the
World very extravagant hcads> the vanities of whom oughti not to
rcdourvd to the prejudice of y^riylo^/fl , of wholti my thinks yoii
fpeak fometimes with too little Tefpeft , and the onely antiquity
and bare nxa*^ that he hath acquired in the opinions of fo many
i^mous men , (hould fuffice to raider him jionoural?l<s with all
that profeflethemfelves learned. ^: : : . :

S A L V. You ftate not the matte? rightly , SimpJicitts There
fome of his followers that fear before they are in 4*^nger,
give us occafion , or, to fay better , would give us qaufe to
^emhim leffe, (hould weconfent to applaud their Capricious.
And you , piay you tell me , are you for your part fo fimple , as
nlq^ '^^"^w that had Artiiotle been pfckat , to have he^d the
uu^^*^ would have made him Author of the Telefcope , he
Jl^ould have been much more difplcafed with himf than with thofe,
langhtat the Doftor and his Comments^ Do you queftioa

whe-

Chymifis inter'
pret the Fables of
theFoetf te be [c
cr its for maki»g of

Some of A rift 0-
tles Senators im-
pare the repmatton
of their Mafier-ttn
going aboHt to en'
hanfe it.

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2°K.B. 9,163

C. G A L I L u his .:jycme.
whether yir//l^^/e, had he but feen the novelties dilcoveicd in Hea-
ven would not have changed his opinion, amended his Books,
and embraced the more fenfible Doftrine rejcding thofe filly
Gulls, which too fcrupuloufly go about to defend what ever he
hath faidi not confidering, that if Anfiotlc were fuch a one as
they fancy him to themfelves , he would be a man of an untraaa-
ble wit an obftinate mind , a barbarous foul , a ftubborn will,
that accounting all men elfe but as filly flieep , would have his
Oracle^ preferred before the Senfes , Experience, and Nature her
felf ? They are the Seaators of Ari^i ot le th^it have given him this
Authority , and not he that hath ufurped or taken it upon him ;
and bccaufe it is more eafie for a man to fculk under anothers
fliield than to (hew himfelf openly , they tremble , andareaftraid
to ftir on^ ftep from him i and rather than they will admit fome
alterations in the Heaven of Ariftotle , they will impertinently de-
ny thofe they behold in the Heaven of Nil^«re.

S A G R. Thefe kind of Drolleries put me in mind of that Statu-
ridicHhw ^hich having reduced a great piece of Marble to the Image of
^£.f znHercHles , or a thundring>]>i^^r , I know not whether , and
given it with admirable Art fuch a vivacity and threatmng fury,
dbat it moved terror in as many as beheld it he himfelt began
alfo to be aflPraid thereof, though all its fprightfulneffe , and life
was his own workmanfliip-i and his affnghtment was fuch , that
he had no longer the courage to affront it with his Chizzels and

A L V. I have many times wondered how thefe nice maintain*
crs of wliat ever fell from Arijhotle^ are not aware how great a pre-
judice they are to his reputation and credit ^ and how that the
more they go about to encreafe his Authority, the more they
diminifh it 5 for whileft I fee them obftinate in their attempts
to niaintain thofe Propofitions which I palpably difcover to
be inanifieftly frife.5 and in their defires to perfwade me that
fotpdo, is the part of a Philofopher^ and that Ariftotle himfelf
would da the fame, it much ^^^^^^ in me of the opinion that , he
hatfci-khtly philofojphated about othervConclufions, to ine more
abftrufe : (or if I could fee them concede and change lojpinion in
a maiiifcft truth, 1 would believe, that in thofe in which they
fliould jperfift) they may have fome folid demonftrations. to me an-
known^^and unhdard of. •

S A G Or when they fliould be made to fee that tiley have Jik-
zarded. too much of their own and Ariftotle s repu^tation in con'
fefllbg^Wt they had notunderfiood this or that conclufion foua^l
out by fome other man j would it not be a lefs evil for them to
feekfor it amonfft his Texts, by laying many of them together^
according to the art intimated to us by Simplicim} for if bfc

work«

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2°K.B. 9,163

I A LOG U F.

I in

Works contain all things knowablc , it muft follow alfo that they
l)*ay be therein dilcovcred.

S A L V. Good SdgredH^, make no jeft of this advice, which mc
thinks you reliearfe in too Ironical a way for it is not long fince
that a very eminent Philofopher having compoicd a Book de ammj,
wherein, citing the opinion of AnJiotLe, about its being or not be-
ing immortal, he alledged many Texts, (not any of thofe hereto-
fore quoted by Alexander ab Alexandra : for in thofe he faid, that
Arijlotle had not lb much as treated of that matter, much lefs de-
termined any thing pertaining to the faine, but others) by hirafelf
found out in other more abftrufc places, which tended to an er-
roneous feafe : and being advifed,that he would find it an hard
matter to get a Licence from the Inquifitors , he writ back unto a hraverefolu-
m$ friend,, that he would notwithftanding , with all expedition p'^i^'^ctfck^r
procure the lame, for that if no other obftacle fliould intcrpofe, /J'^/;.'?'
he would not much fcruplc to change the Doftrine of ^ri/Ic?//e >
with other cxpofitions , and other Texts to maintain the con-
trary opinion , which yet {hould be alfo ^rccablc to the fcnfc of
Avtftotle.

S A G H- Oh moft profound Doftor y this I that can command
methatlftir not a ftep from ArtfiotU , but will himfclf lead
him by the nofe , and make him fpeak as he plcafeth. See how
much it importeth to learn to take time by the Fare-tajp. Nor
is it leafonable to have to do with Hercules y whifft he is en-
raged, and amongft the Furies, but when he is telling merry talcs
amongfl the Meonion Damofeh, Ah, unheard of fordidneffe of
iervileiouls 1 to make themfelvcs willing flaves to other mens opi-
nions j to receive them for inviolable Decrees , to engage thcra-
iclves to leem fatisfied and convinced by arguments , of fuch effi-
cacy , and lo manifeftly concludent , that they tbemfclves can-
not certainly relblve whether they were really writ tothatpur-
pofe > or fcrve to prove that alTumption in hand , or the contrary.
But, which is a greater madneffe , they are at variaiKC amongft
thcmfelves, whether the Author himfelf hath held the affirmative
part, or the negative. What is this, but to make an Oracle of a
*-og, and to run to that foranfwers, to fear that, to reverence
and adoi-e that ?

S I M p L. But in cafe we (hould recede from AriSiath , who have
to be our Guid in Philoibphy ? Name you fome Author.
. S A L V. We need a Guid in unknown and uncouth wayea , but
m Champion places , and open plains, the blind only ftand in need

But\ K ' ' ^'^^ ^^^^ ' ^"^^ ^^^^ ^^^y

^ e that hath eyes in his head , and in his mind , him fliould
(^T ^^^^ ^'^^ Guid. Yet miftake me not , thinking that I Too dofe adh-
peak this , for ^hat I am againft hearing of ArijlotU ; for on the f^^Z^l^l^""^^ ^

The fervili fpi*
rtt of fomecf

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2°K.B. 9,163

G. G

ALIL/F. us.

his Syl

erne.

ft if m jujf^that
thofe who f.ever

ftfu-p the title cf

The

contrary, I commend the reading , and diligently ftadying of hiiir,
and onely blame the fervile giving ones felf up a flave unto him,
fo, a.s blindly to fubicribe to what ever he delivers , and without
fearch of any farther reafon thereof, to receive the famefof an in-
violable decree. Which is an abiife , thatcarrieth with it ano-
ther great inconvenience , to wit, that others will no longer take
pains to underftand the validity of his Demonftrations. And
what is more ihameful , than m the middeft of publique difputes,
whileft one perfon is treating of demonftrable conclufions , to
hear another interpofe with a pafTage of Jrijiotle , and not fel-
dome writ to quite another purpoie, and with that to flop the
mouth of his opponent ? But if you will continue to ftudy in this
manner, I would have you lay afide the name of Philofophers ^
and call your felves either Hiftorians or DoSors of Memory , for
it is not fit, that thofe who never philofophate , fliould ufurp
the honourable title of Philofophers. But it is beft for us to re-
turn to fliore 5 and not lanch farther into a boundleffe Gulph, out
of which we fliall not be able to get before night. Therefore
Simflicm-> come either with arguments and demonftrations of
your own , or of Arijiotk:, and bring us no more Texts and na-
Senjikle ked authorities , for our difputes are about the Senfible World,
arid not one of Paper. And forafmuch as in our difcourfes yefter-
d.^ V vve retriev'd tiie Earth from darknelTe, and expofed it to the
open skie , ftiewing 5 that the attempt to enumerate it amongft
thofe which we call Cocleftial bodies , was not a pofition fo foil'd,
and vanquifli't , as that it had no life left in it it followcth next?
that we proceed to examine what probability there is for holding
of it fixt 5 and wholly immoveable , fcilicet as to its entire Globe,
what likelihood there is for making it moveable with fome motion?
and of what kind that maybe. And forafmuch as in this fame
queftion I am ambiguous , and SimpUcius is refolute , as likewife
Arifiotle for. the opinion of its immobility , he fliall one by one

1)roduce the arguments in favour of their opinion , and I will at
edge the anfwers and reafons on the contrary part j and next Sa"
grcdns (hall tell us his thoughts , and to which fide he finds him^
felf inclined. ' J

S A G R. Content provided alwayes that I may referv^ the Ik
berty to my felf of alledging what pure natural reafon fliall fome-
times diftate to me.

S A L V. Nay more 5 it is that which I particularly beg of you,
for, amongft the more eafie, and, to fo fpeak , material confidera-
tiqns , 1 believe there are but few of them that have been omit^
ted by Writers , fothat onely fome of the more fub tie , and re-
mote can be defired , or wanting ^ and to inveftigate thefe , what
other ingenuity can be more fit than that of the moft acute an<J
piercing wit of Sagredm ? S ag

^ D I A L O G U E I L

vS A G R. I am what pleafeth Sdlviatm , but I pray ybu>
kt us not Tally out into another kind of digreflion complemencaU
tor at thii time I am a Philofopher , and in the Schools , not in the
Court.

Sal v. Let our contemplation begin therefore with this conG-
deration, that whatfoever motion may be afcribcd to the Earth,
It IS ncceflary that it be to^s, (as inhabitants upon it , and confe-
quently partakers of the fame) altogether imperceptible , and as if
It were not at all , fo long as we have regard onely to terreftrial
thmgs i but yet it is on the contrary , as necelTary that the fame
morion do fcem common to all other bodies , and vifible ob-
KCts , that being fepafated from the Earth, participate not of the
lame. So that the true method to find whether any kind of motion
may be afcribed to the Earth , and that found , to know what it
js , is to confider and obferve if in bodies feparatcd from the
Earth, one may difcover any appearance of motion , wkiche-
quaily iuitcth to all the reft ; for a motion that is onely feen, <v.gr.
m the Moon , and that hath nothing to do with Venus or Jufiter^
or any other Stars, cannot any way belong to the Earth , or to
any other fave the Moon alone. Now there is a moft general and
grand motion above all ethers , and it is that by which the Sun,
the Moon, the other Planets , and the Fixed Stars , and in a word^
the whole Univerfc , the Earth onely excepted , appearethin our
thinking to move from the Eaft towards the Weft , in the fpace of
twenty four hours i and this, as to this firft appearance , hath no
obftacle to hinder it, that it may not belong to- the Earth ^lone,
as well as to all the World befides , the Earth excepted i for the
Jame afpefis will appear, in the one pofition, asin the other.
«ence itis.that^r//J(?f/^and Ptolomy , as having hit upon this con-
uderation, in going about to prove the Earth to be immoveable,
argue not againft any other than this Diurnal Motion j fave onely
^^nAriflotle hinteth fomething in obfcure terms againft another
Motion afcribed to it by in Ancient , of which we fliallfpeakin
Its place.

^ S A G R. I very well perceive the neceflity of your illation : but
^e^t with a doubt which I know not how to free my felf from,
and this it is, That Copernicm afligning to the Earth another mo-
Jon betide the DiurnaU which, according to the rule even now laid
P^^JJ'^^g'^^^obe tous, as to appearance, imperceptible in the
^rth, but vifible in ^11 the reft of the Worlds me thinks I may
"^/^^"lyi^^fcr, either that he hath manifeftly erred in affigning
fn ^ motion, to which there appears not a general corre-

ponaence in Heaven ^ or clfe rfiat if there be fuch a congruity

fn!-^^^"V ^''^""^-^ other hand hath been deficient in not con-
^tmg this, as he hath done the other.

N Salv.

Tfjf matiofft of
toe Earth are im-
perceptible to its
inhabitants.

The Earth cM
hdv^na other mo'-
tmMf y than thofe
-Pfhtch to w appear
commttne to all the
rri? of the Z)m^
-^'rfe , the Sartb
excepted.
T he Diurnal Mo"
feemethcom-
mune to all the V"
ffiverfe, fave oMely
the 8 arth excepted.

Ariftotle and
Pcolomy ar^uea"
g^infi the DtHr-
MnioH attri'
^^ttdto$he£4rfh.

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

yvhy the dinrnal
motion more pro-
b^yij jhofiU belong
to the Earthy than
to the refl of the
'ZJnivirfe,

things that cqnallj
move therehy^ is as
tftt never Wire, &
(afur operates 04 it
hath 7 d Alton to
things deprived rf

G. Galiljeus, hisSyjlcwe.
S^, V -Youhavc^oodcaufe for your doubt : and ^^hen we
come to treat of the other Motion, you (hall lee how far G.^r-
^Zc^cM Ft olomey in clearnefs and lublimity of wit m that
SeTaw what the other did not, I mean the admirable harmony
wherein that Motion agreed with all the other Coeleftial bodies.
Butfortheprefentwe wiUfufpend this particular, and return to
ou firftconllderation ; touching which; will proceed to propofc
fbeoining with things more general) thole reafons which leem to
favTr d?e mobility If the Earth, and then wait the anfwers which
sZ!i!tns fcall make thereto. And firft, if we confider onely
the immcnfe magnitude of the Starry Sphere, compared to the
fmalnefsof theTerreftrial Globe, contained therein io many mil-
lions of limes i and moreover weigh the velocity " of the tnotiou
which muft in a day and night make an entire revolution thercot,
1 cannot perfwade my fclf, that there is any man who believes it
more realbnable and credible, that the Cocleftial Sphere turned
round and the Terreftrial Globe ftands ftiU.

S A G R If from the univerfality of efFeds, which may in nature
' have dependence upon fuch like motions, there ftouW i^difFerent-
W foUow all the fame confequences to an hair, afwell m one Hypo-
7fce? as in the other , yet I for my part, as to my firft and general
rpprehenfion,wouldefteem,thathewhichftouldholditmore ra-
TP ,^^ „ake the whole Univerfe move, and thereby to falve the
p«ths mobility, is more unteafonable than he that being got to
the top of your Turret, (houlddefire, to the end onely that he
miehtljehold theCity, and the Fields about it, that the whole
Country might turn round, that fo he might not be put to the
trouble to ftir his head. And yet doubtlefs the advantages would
be many and great which the Cofermcan Hypothefu is attended
with, above thofe of the Ptolomaiquc, which in my opinion re-
fcmbktb nayfurpaffcth that other folly; fo that all this makc<
me think that far more probable than this. But haply Ariftotlt,
Ftelomy, ^adSimfhcm may find thb advantages of their Sy-
fteme which they would do well to communicate to us alio, »
any fuch there be i or elfe declare to me, that there neither are ot

can be p^^^y"^^, as 1 have not been able, as much as I hav«
thouUt upon it, to find any diverfity therein ; fo I think I
found, that no fuch diverfity can be in them -.m fomuch that J
eft "em it to no purpofe to feek farther after it. Therefore ob
ferve >. Motion is fo far Motion, and as Motion operatcth, by ho^
far it hath relation to things which want Motion : bnt in thoU
things which all equally partake thereof it hath nothmg to do, anO
isasif it never were. And thus the Merchandiles with which *
(hip is laden, fo far move, by how far leaving London, they pal

I A L O G U E

Sit*

t>y France^ Spam-, Italy ^ and fail to Aleppo^ which London^France^
Spjin c^c. ftand ftill, not moving with the fhip • but as to the
Cheli.^, Bales and other Parcels, wherewith the fhip is ftow'd and
and laden, and in refpeft of the fhip it felf, the Motion from Lon-
dohi to Syria is as much as nothing ^ and nothing-altercth the re-
lation which is between them : and this^becaufe it is common to
all, and is participated by all alike ; avid of the Cargo which is in
the fhip, if a Bale were romag'd from a Cheft but one inch onely,
this alone would be in that Cargo, a greater Motion in refpeft of
the Cheft, than the whole Voyage of above three thoufand miles,
made by them as they were ftived together.

S I mS>^/ This Doftrine is good, found, and altogether Fen-
patctkl^

S al v. 1 hold it tobemuch morcantient : and fufpeO: that A-
njiotle in receiving; it from fome good School, did not fully under-
ftand it, and that therefore, having delivered it with fomc altera-
tion, it hath been an occafion of confufion amongft thofe, who
would defend whatever he faith. And when he writ, that what-
foever moveth, doch move upon fomething immoveable, I fuppofe
that he equivocated, and meant, that whatever moveth, moveth
in reTpefi: to fomething immoveable y which propofition admittcth
no doubt, and the other many.

S A G R. Pray ycki make no digreffion, but proceed in the dif-
fertation you began.

Salv. It being therefore manifcft, that the motion which is
common to many moveables, is idle, and as it Were, null as to the
relation of thofe moveables between themfelves, becaufe that a-
mong themfelves they have made no change : and that it is 6pe-
rative onely in the relation that thofe moveables have to other
things, which want that motion, among which the habitude is
changed : and we having divided the Univerfe into two parts, one
of which is neceffarily moveable, and the other immoveable i for
the obtaining of whatfoever may depend upon, or be required
from fuch a motion, it may as well be done by making the Earth
alone, as by making all the reft of the World to move : for that
the operation of »fuch a motion confifts in nothing elfe, fave in
the relation or habitude which is between the Coeleftial Bodies,
^nd the Earth, the which relation is all that is changed* Now if
^or the obtaining of the fame efFeft adunguem^ it be all one whe-
Jl^^r the Earth alone moveth, the reft of the Univerfe ftanding
\ or that, the Earth onely ftanding ftiH? the whole Univerfe
moveth with one and the fame motion 5 ^ho would believe, that
Nature (which by common confent, doth not that by many thiiags,
which may be done by few) hath chofen to make an innumerable
*^umbcr of moft vaft bodies move, and that with an unconceivable

A propoJitiontM*
k?n hy Ariltocle
from the Aniienn^
dm fomenphat al-
ter:dhj htm.

The firfl dtfcoftrp
to prove that the
difirnal motion he-
longi to the Earth,

Natttre never
doth that hj ^anj
things^ vfhich ffta^
hdonehj afeW'

N 3

velocity^

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

IOC

mutation amoft^fi
the CoeUfital Bo-
dies^ hm all eh an-
ges have relation
to the Sarth-

G. G A L I L ^ u s, }yis Syflcme.

velocity, to perform. that , which might be done by the moderate
motion of one alone about its own Centre ?

S I M p L. 1 do not well underftand, how this grand motion fig-^
niheth nothing as to the ^un, as to the Moon, as to the other Pla-
nets, and as to the innumerable multitude of fixed ftars : or why
you fliould fay that it is to no purpofe for the Sun to pafs from one
Meridian to another i to rile above this Horizon, to fet beneath
^lat other \ to make it one while day, another while night : the
like variations are made by the Moon, the other Planets, and thej
fixed ftars themfelves- . ;j

S A L V. All thefe alterations inftanccd by you, are nothing, fav|j
oncly in relation to the Earth : and that this is true, do but
rhediurnaimo^ magiue the Earth to move, and there will be nofuch thing in the
thn caufeth Woild ^is the rifing or fettir>g of the Sun or Moon, nor Horizons,
nor Meridians^ nor days, nor nights j nor, in a word, will fueh a.
motion caufe any mutation between the Moon and Sun, or an
other jftar whatfoeyer, whether fixed or erraiick^ but all thelc'
changes have relation to the Earth : which all do yet in fum
import; po other than as if the Sun fhould Ihew it fclf. now to
China, 2XiOi\ to Perfidy then to Egypt, Greece, France, Spain, 4j
fnericay&'C, and the like holdeth in the Moon, and the reft of th
Cceleftial Bodies : which fdf fame efFed falU out exa£ily in the""
fame maimer > if> without troubling io great a part of the Univcrfe,
the Terreftrial Globe be made to revolve in it felf. But we will
augment the difficulty by the addition of this other, which is a
very great one, namely, that if you will afcribe this Gi/t^at Motion to
Heaven, you muft of neceffitymake it contrary to the particular
motion of all the Orbs of the Planets, each of which without
controverfie hath its peculiar motion from the Weft towards the
Eaft, and this but very eafie and moderate : and then you make
them to be hurried to the contrary part, i. e. from Eaft to Weft,
by this moft furious diurnal motion ; whereas, on the contrary,
making the Earth to move in it felf, the contrariety of motions is
taken away, and the onely motion from Weft to Eaft is accom"
modated to all appearances, and exaftly fatisfieth every Plmno^

meuon. r ■

S I M p L. As to the contrariety of Motions it "would import lie
Za' tie , for AriJiotU demonftrateth,that circular motions, are not cq|I
- trary to one another ; and that theirs cannot be truly called coiP
tr^riety.

S A i V. Doth Arijlotk demonftrate this , or doth he not rather
barely affirm it , as ferving to fome certain defign of his ? If con'
traries be thofe things, that deftroy one another, a? he himfclf
affirmeth , 1 do not fee how two moveables that encounter each
other in a circular line, £l\ould leife prejudice one another , than
th^y interfered in a right line. S a g

A fcceni con-
firmatkn that the
dtHYndl motion bs-
longsiothe Earth.

^trcuUr moth
ons are not contra-
Yj , according
Ariftodc.

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

Dialog tii. IL

Sagr. Hold a little 5 1 pray you. Tell me , when

two Knight.

whe

two J

► you call thefe encounters contrary to

encounter each other, tilting
two whole Squadrons ~"
and arc broke*n and i'ui
one another ?
> S I M p L. Yes, we fay they arc contrary.

Sagr. How then , is there no contrariety in circular motions.
1 heic motions , being made upon the fuperhcies of the Earth or
.Water , which are , as you know , fpherical , come to be circular.
Can you tell , SimpliciHS^ which thofe circular motions, be , that
are not contrary to each other ? They are (if I miltake not) thofe
two circles , which touching one another without, one thereof
being turn d round, naturally maketh the other oiove the contra-
jy * way 5 but if one of them (hall be within the other ? it is im-
poffible that their motion being made towards different points ,
they fliould not )uftle one another.

S A L V. But be they contrary , or not contrary , thefe are but
alterations of words j and I know , that upon the matter, it would
be far more proper agreeable with Nature , if we could falve
all with one morion onely , than to introduce two that are (if you
will not call them contrary) oppofite yet do I not cenfure this
intfoduftion (of contrary motions) as impoITible ^ nor pretend I
from the denial thereof, toinfcrre aneceffary Demonftration ,
but onely a greater probability , of the other. A third reafon
which maketh the TtQlomaiqiie Hypothefis Icffe probable is, that it
moft unreafonably confoundeth the order , which we a{ruredly
lee to be amongft thofe Coeleftial Bodies the circumgyration of
vvhich is not queftionable , but moft certain. And that Order is,
that according as an Orb is greater , it finiflieth its revolution in a
longer time , and the lelTer, in (horter. And thu^ Saturn defcri-
bing a greater Circle than all the other Planets , compleateth the
lame in thirty yeares: Jupiter finifheth his that is lefle , in
Uvelve years : Mars in two : The Moon runneth thorow hers , fo
much lefle than the reft , in aMoneth onely. Nor do we leffc
lenhbly lee that of the Medicean Stars, which is neareft to Jn^
pter , to make its revolution in a very (hort time , that is> in four
^nd forty hours, or thereabouts, the next to that in three dayes and
an half, the third in feven dayes , and the moft remote in fixteen.
Andihis rate holdeth well enough , nor will it at all alter , whileft
^« aaign the motion of 24 hours to the Terreftrial Globe , for it
I? ^ove round its own center in that time j but if you would havp
Larch immoveable , it is neceffary, that when you have paft
tromthe ()^ort period of the Moon , to the others fucceffively
jigger , Until you come to that of Uars in two years , and from
^^ftce t;o that of the bigger Sphere of Jupiter in twelve years, and

from

* As yoa fee in ^
Mill , wherein che
impiicKcd cogs let
the wheels en mo-
ving;.

^ third eonfir-
mutton of the f^mc
Dotirtne.

The ^reAltr Orh
make their conver'
fions in greatn
times.

The times of the
Mcdiccan PUneti
converCior,}.

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

I02L

The motion of
14 hoars ajcrthed
ta the hii^hejt
Sphere difo-dsrs
the period of the
inferiotir.

The fourth Qr^'
Jirmatton.

Grcdt dtfpartty
amojigft the moti-
ons of the part tcfi'
Ur fixed fiarf , if
thiir Sphere he
moveable'

7 he fifth Con-
frmntton.

The ntoti'jns of
tht fixed J^-trs
Tvonld accelerate
and grow flow tn
divers times^ tfthe
ftarry Sphere vpere
moiieahle.

The fixth Con-
''rm»tioft*

C: G A L 1 L /E u s, bis Syjleme.

•from thi^ to the other yet bigger of Salnrn , whofe period is of
thirty years / it is neceflary , I lay , that you paffe to another
Sphere incomparably greater ftill than that , and make this to ac-
compUni an entire revolution in twenty four hours. And this yet is
the leaft diforder that can follow. For if any one fliould pafle
from the Sphere of Satuni to the Starry Orb , and make it fo
much bi^racr than that oi^alnrti , as proportion would require, m
refpeftof its very flow motion, of many thouiands ot years , then
it muft needs be a Salt much more ablurd , to skip irom this to
another bigger , and to make it convertible in twenty four hours.
But the motion of the Earth being granted , the order of the pe-
riods will be cxaaiy obkrved , and from the very flow Sphere of
Saturn ^ vve come to the fixed Stars , which are wholly immovea-
ble and fo avoid a fourth difficulty, which we muft of neceffity ad-
mit if the Starry Spliere be fuppofcd moveable, and that is the
immenfe difparity between the motions of thofe ftars themfelves^
of which fome would come to move moft fwiftly inmoft vaft cir-
cles , others moft flovvly in circles very fmall , according as thofe
or thefe fliould be found nearer , or more remote from the Poles ^
which ftill is accompanied with an Inconvenience , as well becaule
we fee thofe , of whofe motion there is 110 que ft ion to be made,
to move all in very immenfe circles i as alfo, becaule it feems to
be an aft done with no good confideration , to conftitute bodies,
that arc defigned to move circularly , at immenfe diftances from
the centre , and afterwards to make them move in very fmall cir-
cles. And not onely the magnitudes of the circles , and confe-
quently the velocity of the motions of thefe Stars , fliall be moft
different fiom the circles and motions of thole others , but
( which fliall be the fifth inconvenience ) the felf-fame Stars
fliall fuccellively vary its circles and velocities : For that
thofe , which two thoufand years fince were in the Equinofliah
and confequently did with their motion defcribe very vaft cir-
cles being in our dayes many degrees diftant from thence, muft
ofneccflity become more flow of motion , and be reduced to
move in leffci* circles , and it is not altogether impoflible but that
a time mav come , in which fome of them which in aforetime had
continually moved , fliall be reduced by uniting with the Pole, to
a ftate of reft , and then after fome time of ceffation, fliall return
to their motion again j whereas the other Stars, touching whofe
motioa none ftand in doubt , do all defcribe , as hath been faid>
the great circle of their Orb , and in that maintain themfelves
without any variation. The abfurdity is farther enlarged (which
let be the fixth inconvenience) to him that more ferioufly exami-
iicth the thing , in that no thought can comprehend what ought to
be the folidity of that immenfe Sphere , whole depth fo ftedfaftly

holdetb

cir-

. to

D I A L O G U E. I L
holdcth faft luch a multitude of Stars, which without evjr chang-
ing lite among thcmlclvcs , are with lb much concord carried a-
bout 5 with fo great difparity of motions. Or elic, luppofing the
Heavens to be fluid , as we are with more reaibn to beheve , io
as that every Star wandereth to and fro in it , by wayes of its
own , what rules fhall regulate their motions , and to what pur-
pofe y fo, as that being beheld from the Earth , they appear as if
ihey were made by one onely Sphere > It is my opinion, that they
might fo much more cafily do that , and in a more commodious
manner , by being conftituted immoveable , than by being made
errantjby how much more facile it is to number the quarries in the
Pavement of a Fia'x*%»j , than the rout of boycs which run up and
down upon them. And laftly , which is the feventh inftance , if
wc atribute the Diurnal Motion to thehigheft Heaven , it muft be
conftituted of fucha Torce and efficacy , as to carry along with
it the innumerable multitude of fixed Stars , Bodies all of vaft
magnitude , and far bigger than the Earth i and moreover all the
Spheres of the Planets ^ notwithftanding that both thefe and thofe
of their own nature move the contrary way. And befldes all this,
it muft be granted , that alfo the Element of Fire , and the great-
er part of the Air, are likewife forcibly hurried along with the
reft 9 and that the fole little Globe of the Earth pertinacioufly
ftands ftill, and unmoved againft fuch an impulfe ^ a thing , which
in my thinking , is very difficult 5 nor can I fee how the Earth, a
pendent body , and equilibrated upon its centre , expofed indif-
ferently to either motion or reft , and environed with a liquid am-
bient , (hould not yield alfo as the reft , and be carried about.
But we find none of thefe obftacles in making the Earth to move;
a fmall body , and infenfiblc , compared to the Univerfe , and
therefore unable to offer it any violence.

S A G R. I find my fancy difturbed with certain con jeftures fo con-
fufedly fprung from your later difcouifes , that, if I would be ena*
bled to apply my felf withatention to what foUoweth,! muft of ne-
cefflty attempt whether I can better methodize them , and gather
thence their true confttuQion , if haply any can be made of them3
and peradventure, the proceeding by interrogations may help me
the more cafily to expreffe my felfTherefore I demand fifft of S//^-
fliciHs 5 whether he believcth 1 that divers motions may natural-
ly agree to one and the fame moveable body, orelfe that it be
^quifite its natural and proper motion be onely one.
, S I M P L. To one fingle moveable , there can naturally agree
but one fole motion , and no more the reft all happen acciden-
tally and by participation like as to him that walketh upon the
Deck of a ship , his proper motion is that of his walk , his motion
by participation that which carrieth him to his Port , whither hfp

would

103

The Seventh Co»^
firnfMtiei.

7 he Earth 4

pendent *Body^ and
ecjuilibr^ed in a
fiftid Medium
feems ttMakle to
refifi the raptnre
of the Dmrndl
Afotion,

A fingltmove"
able hath but onely
one natural moti-
on , and all the
refl are by partict"
pal ton.

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

IC4 G. G ALU us /bis Syfieme.

would never with his walking have arrived , if the Ship with its
motion had not wafted him thither.

vS A G K. Tell me fecondly. That motion , which is communi-
cated to any moveable by participation 5 v^hileft it moveth by it
felf, with another motion different from the participated , is it
neceffary , that it do refide in fome certain fubjeft by itfelf, or
elfc can it fubfift in nature alone , without other fupport.
i^otion edfmot S I M p L. Atiflotle givcth you an anfwer to all thefe queftions,
h^. made rvithoHt and tcls you 5 that as of one fole moveable the motion is but one \
its moveable fub- ^j^^ motion the moveable is but one , and confequent-

^' ' ly, that without the inherence in its fubjeft , no motion can ei-

ther fubfift 5 or be imagined.

S A G R. I would have you tell me in the third place, whether
you beblieve that the Moon and the other Planets and Ca:leftial
bodies 5 have their proper motions , and wh* t they are.

S I M p L. They have fo , and they be thofe according to which
they run through the Zodiack , the Moon in a Moneth , the Sun
in a Year , Mars in two , the Starry Sphere in thofe fo many thou-
fand. And thefe are their proper, or natural motions.

S A G R. But that motion wherewith I fee the fixed Stars , and.
with them all the Planets go unitedly from Eaft to Weft , and rCr
turn round to the Eaft again in twenty four hours , how doth it
agree with them ?

SiMP L. It fuiteth with them by participation.

S A G R. This then refides not in them , and not refiding in
them 5 nor being able to fubfift without fome fubjed in which it
isrefident , it muft of foree be the proper and natural motion of
fome other Sphere.

SiMPL. For this purpofe Aftronomers , and Philofophers have
found another high Sphere , above all the reft 5 without Stars , to
which Natural agrceth the Diurnal Motion , and this they call
the Piimtim mobile , the which carrieth along with it all the in-
feriour Spheres , contributing and. imparting its motion t
them.

S A G R. But when, without introducing other Spheres unknown
and hugely vaft, without other motions or communicated raptures,
with leaving to eacji Sphere its fole and fimple motion, without
intermixing contrary motions, but making all turn one way, as
it is neceffary that they do, depending all upon one fole principle,
all things proceed orderly, ^ind correfpoiid with moft perfefl: har-
mony, why do we rejeft this Fhoenonienon^ and give our affent to
thofe prodigious and laborious conditions ?

S I M p L. The difficulty lyeth in finding out this fo natural and
expeditious way.

nt-

re-

Dialogue I !•

Sag f:. In my judgment this is found. Make the Earth the:
frimum mobile^ that is, make it turn round its own axis in twenty
four hours, and towards the fame point with all the other Spheres j
and without participating this fame motion to any other Planet or
Star, all fhall have their rifings, fettings, and in a word, all their
other appearances.

S I M p L. The bufinefs is, to be able to make the Earth move
without athoufand inconveniences.

Sal v. All the inconveniences fhall be removed as fall as you
propound them : and the things fpoken hitheao are onely the
primary and more general inducements which give us to believe
that the diurnal converfion may not altogether without probabi-
lity be applycdto ihe Earth, rather than to all the reft of the U-
niverfe : the which inducements 1 impofe not upon you as invio-
lable Axioms, but as hints, which carry with them fomcwhat of
likelihood. And in regard I know very well, that one fole ex- o»e fmglax^
periment, or concludent demonftration, produced on the contrary ' <^[ouni

r\..rrr^ii t -x \ r \ I'l demon ft rat ion bmi'

part, lutticeth to batter to the gtound thetc and a thouland other ttrethdot^naiiar^
probable Arguments^ therefore it is not fit to ftay here, but proceed nnerly
forwards and hear what •Siwjj/ic/^^ anfwereth, and what greater ^''"'^^^^^^
probabilities, or ftronger arguments he alledgeth on the contrary.
♦ S I M p L. I will firft fay fomething in general upon all thefe con-
fidcrations together, and then 1 will defcend to fome particulars.
It fcems that you univerfally bottom all you fay upon the greater
fimpiicity and facility of producing the fame effefts, whilft you
hold, that as to thecaufingof them, the motion of the Earth a-
lone, ferveth as well as that of all the r^ft of the World, the Earth
deduced : but as to the operations, you efteem that much eafier
than this. To which I reply , that I am alfo of the fame opinion,
fo long as f regard my own not onely finite , but feeble power i
but having a refpeft to the ftrength of the Mo<ver , which is in-
"nite , its no lefl'e cafie to move the Univcrfe , than the Earth,
yea than a.ftraw. And if his power be infinite , why fliould he not c>/ an i^nnite
rather excrcife a greater part thereof than a lelTe ? Therefore, former on/Tonld
I hold that your difcourfe in general is not convincing. 'r^nfhtuKlXr
S A L V. If I had at any time faid , that the Univerie moved not ^eimfUfd "thsnd
lor want of power in the Mo^er ^ Ifliouldhave erred, and your
reproof would have been feafonable, and I grant you, that to
infinite power, itisaseafie to move an hundred thoufand, as
But that which I did fay , concerns not the Mover , but one-
y hath tefpeft to the Moveables h and in them , not onely to
^J^'f '^fiftance , which doubtleffe is lefler in the Earth, than in
the Univeife j but to the many other particulars , but even now
conlidcred. As to what you fay in the next place , thatfcf anin-
nmte power it is better to exercife a great part than a fmall : I an-

fwef,

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

io6

cf i»fi»''tr,

pAn u no ytgger
than another i al-
though they are
comparatively un*
fqual.

G. Galil/eus, h'tsSyjlam.

fwer, thatofinfuiite one part is not greater than another , fincc
hofh are infinite ■■, nor can it be laid , that of the infinite number,
anhundred thoufand is a greater part.than two, thoughthatbe
fifty thoufand times greater than this ; and .f to the moving of
the Univerfc there be required a finite power, though very great
incomparifon of that which fufliceth to move the Earth onelyi
yet is there not implied therein a greater part of the infinue power,
nor is that partkffe infinite which remameth unimploy d. bo that
to apply unto a particular effea , a little more , or a little leffe
power iroporteth nothing; befides that the operation of fuch
vertue', hath not for its bound or end the Diurnal Motion onelyi
but there arc feveral other motions in the World , which we
know of , and many others there may be, that are to us unknown:
Therefore tf we refpeft the Moveables , and granting it as out of
queftion , that it is a flrorter and eafier way to move the Earth,
than the Univetfe i and moreover, having an eye to the fo many
other abreviations, and facilities that onely this way are to be ob-
tained an infallible Maxime of A rifiotle , which he teacheth us,
that, frnftra fit ferplnra, qnod poteft fien fer pandora, ren^
dcreth it mori probable that the Diurnal Motion belongs to t
Earthalone, thantotheUniverle, theEarthfubduded.

S I M p L In tectting that Axwm , you have omitted a fmall
claufe wbich importcth as much as all the rcll , efpecialiy in ou
fe that is to fay, the words ^qu^ bene. It is requifitc therefd
to examine whether this Hypothefis doth equally well faiisfie in all
partimlars, as the other. , , , , ^

S A L V. The knowlcdg whether both thele pofitions do <gqMt
bene fatisfie, maybe comprehended from the particular exami^
nation of the appearances which they are to fatisfie i for hitherto
we have difcouifed , and will continue to argue ex" hypotheft i
namely, fuppofing, that astothefatisfaaionof the appearances
u^bcAxion., both the affumptioHs are equally accomodated. As to the claufe
Fruftiafit perpiu- you fay was omitted by me , 1 have more reafon to lulpea

";,?-4:bet that it wasfuperfluouflyinfertedbyyou. For the expreflion^^-i
i,frf(rfHm,. j^^j is a relative that ncceffanly requireth two terms at lealt)
for a thine cannot have relation to its felf , nor do we fay, v. gr.
reft to be equally good, as reft. And becaufe , when we fay, that
done in vain by many means, which may be done with fewel^i
we mean , that that ^*hich is to be done , ought to be the fame
thing, not two different ones i and becaufe the fame thing can*
not be faid to be done as well as its felf ; therefore, the additioj
of thePhrafe ^que bene is(a^et(iaoas ^ and a relation , that hatB

but one term onely. r i r i rL ^

Sagr. Unleffeyou will have the fame befal us , as did yett<i*
day , let us return to cm- matter in hand i and let SimpUcimbe*
^ gin

I A L O G U E

107

; opinion.

gin to produce thofe difficulties that feem i
this newdifpofitionof the World.

S I M F L. That difpofition is not new , but very old ^ and. that
you may fee it is fo , A r ijiot le con(\itcth it ; and his confutatioqs
are thefe : Firft if the Earth moveth either in it felf about its
own Centre , or in an Excentrick Circle, it is neceffary that that
" lame motion be violent ^ for it is not its natural motion , for
''if it were, each of its parts would partake thereof 3 but. each
of them moveth in a right line towards its Centre. It being
" therefore violent and pteternatural , it could never be perpetu-
al : But the order of the World is perpetual. Therefore, c^^c.
'" Secondly , all the other moveables that move circularly , feem
* to * ftay behind , and to move with more than one motion , the
trimnm Mobile excepted : Whence it would be neceffary that
" the Earth alfo do move with two motions ; and if that fliould
" befo, it^would inevitably follow , that mutations fliould be
' made in the Fixed Stars , the which none do perceive nay
without any variation , the fame Stars alwayes rife from cowards
" the fame places, and in the fame places do fet. Thirdly, the mo-
tion of the parts is the fame with that of the whole, and natural-
" ly tendeth towards the Centre of the Univerfe j and for the fame
t<= caufereft, being arrived thither. He thereupon moves the que-
^' ftion whether the motion of the , parts hath .a tendency to the
" centre of the Univerfe, or to the centre of the Earthy and conclu-
« deth that it goeth by proper inftinft to the centre of the Univerfe,
" and per accidence to that of the Earth j of which point we largely
'^'^ difcourfed yefteiday. He laftly confirmeth the fame with a fourth
argument taken from the experiment of grave bodies, which fal-
mg from on high,defcend perpendicularly unto the Earthsfurfacej
' and in the fame manner ProjeBzons (hot perpendicularlyupwards,
do by the fame lines return perpendicularly down again, though
they were fliot to a very great height. All which arguments nccef-
farily prove their motion to be towards the Centre of the Earth,
which without moving at all waits for , and receivcth them. He
intimateth in the laft place that the Aftronomers alledg other
I' reafons in confirmation of the fame conclufions , I mean of the
Earths being in the Centre of the Univerfe , and immoveable^
and inftanceth onely in one of them to wit, that all the Phx^
^^^nomeua or appearances that are feen in the motions of theStars^
agree with the pofition of the Earth in the Centre^
ic Th ^ would not be fo , were the Earth fcated otherwife.
^^'^rcftproducedbyFWt?^;; and the other Aftronomers, jcan
pve you now if you pleafe , or after you have fpoken what you
have to fay in anfwerto thefe of Arifiotk.
V A L V. The arguments which are brought upon this occafion

O 2 are

Arid odes e^r*
gnmemi for th»
Eanhs <jutcjfctfce.

* Rejltns tndiet^9^
which is mean:
here of thac moti-
on which a bovvl
makes when i'-s
born by ics byas to
one hde or other,
anJ {'0 hindered ia
iisdircvSi motion.

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

io8

. Tvpo kjtides cf
^^rguments tOH'
chwff the Earths
motion or rest'

^Arguments of
Ptolomy and. Ty-
x\\0'iahd other p.T-
Jons , over And, 4-
hovethofe of Ari-
rtode.

The flrfi argti-
raent tak^fi from
grave bodies fal'
ling from on high
to the ground.

fphich is confir-
med by the experi-
ment of a body let
fall from the roHvd
top of a Ship.

* that is, at the
foot of the Ma(i,
upon the upper
deck.

The fecond ar-
^nment taken from
a Projection [hot
very high.

The third argti'
ment taken frotrs
the fhots of a C^»'
mn , towards the
Eafl; and towardi
thefVeH.

G, G A L I L u his Sjjieme.

are of two kinds : fomc have refpcfl: to the accidents Terreftrial,
without any relation to the Stars , and others are taken from the
Fhdenomena and obfervations of things Coelcftial* The arguments
of Ariflotk 'dSQiox the moft part taken from things neer at hand,
and he leaveth the others to Ajironomcrs j and therefore it is the
beft way, if you like of it, xo examine thefe taken from experi-
ments touching the Earth, and then proceed to thole of the other
kind. And becaufe Tycho ^ and the other Ajironomcrs

and Philofophers., befides the arguments of Ariflotle by them affu-
medj confirmed, and made good, do produce certain others , w,
will put them all together? that fo we may not anfwer twice to
the fame, or the like objeflions. Therefore Simplicim-i choofe
whether you will recite them your felf, or oaufe me to eafe you of
this task, for I am ready to ferve you.

S I M p L. It is better that you quote them , bccaufe, as having
taken more pains in the ftudy of them, you can produce them wit.
ittore readineffe, and in greater number.

Sal v. All, for the ftrongeft reafon, alledge that of grave bo-
dies, which falling downwards from on high, move by a right line,
that is perpendicular to the furf^ce of the Earth , an argument
which is held undeniably to prove that the Earth is immoveable :
for in cafe it fliould have the diurnal motion , a Tower , from the
top of which a ftone is let fall, being carried along by the conver-
fion of the Earth, in the time that the ftone fpends in faUing,would
be tranfpprted many hundred yards Eaftward , and fo far diftant
from the Towers foot would the ftone come to ground. The
which efFeS they back with another experiment , to wit , by let-
ting a bullet of lead fall from the round top of a Ship, that lieth at
anchor, and obferving the' mark it makes where it lights, which they
find to be neer the * partners of the Maft j but if the f^me bullet
be let fall from the fame place when the flilp is under fail , it fliall
light as far from the former place, as the (hip hath run in the time
of the leads defcent , and this for no other reafon, than becaufe
the natural motion of the ball being at liberty is by a right line to-
wards the centre of the Earth. They fortifie this argument with
the experiment of a pro)efl;ion (hot on high at a very great di-
fiance , as for example, a ball fent out of a Cannon, erefted per'
pendicular to the horizon, the which fpendeth fo much time in af-
cending and falling, that in our parallel the Cannon and we both
fhould be carried by the Earth many miles towards the Eaft, fo
tha?t the ball in its return could never come neer the Peece , but
would fall as far Weft, as the Earth had run Eaft. They againe
adde a third, and very evident experiment, fcilicet^ that fhooting %
bullet point blank (or as Gunners fay,neither above nor under me-
tal) put of a Culvcrin towards the Eaft, and afterwards another,

with

Dialog UE. IL

with the fame charge^and at the fame elevation or difporc towards
the Wcftj the range towards the Weft fliould be very much grea-
nts ter then the other towards the Eaft : for that whil'ft the ball gocth

[id, Weftwardj and tlie Pecce is carried along by the Earth Eaftward,

the f he ba,ll will fall from the Pcece as far diftant as is the aggregate of

the twoiBoftons, one made by it felf towards the Weft , and the
other by the Pcece carried about by the Earth towards the Eaft ,
^iid on the contrary,, from the range of the ball (hot Eafiw&rd you
Jij- ace to ftrbftraft the ipace the Peece moved, being carried' kf ter it^

-NowhTppolc, for example, that the range of the ball fhot Weft
vvere hvc miles, and that the Earth in the fame p^irallel and in the
time of the Bals ranging fhould remove three miles,thc Ball in fhis
cafe would fall eight miles diftant from the Gulverin, namcry, its
own five Wcftward, and the Culverins three miles Eaftward : but
ing tie range of the (hot towards the Eaft would be but two miles

Elongj for fo much is the remainder , after you have fubftrafted
from the five miles of the range , the three miles which the Peece
had moved towards the fame part. * But experience fheweth the
ine, Kanges to be equal, . therefore the Ciilverin, and conrcqttently thb

icnt Earth arc immoveable. And the ftability of the Earth is h6 leiffe

de : confirmed by two other ftiots made North and South 5 for they

the would never hit the mark, but the Ranges would be alwayes wide^

^^j.^ or towards the Weft, by meanes of the remove the mark wbuld

mid niake, being carried along with the Earth towards the Eaft, whirft

.^j^^ the ball is flyjng. And not onely (hots made by the Meridians,

fhq \ ^'^^ thole aimed Eaft or Weft would prove uncertain •, for

tbofe aim'd Eaft would be too high , and thofe direfted Weft too
low, although they were {hot point blank, as I faid. for tKtf
Range of the Ball in both the fhots being made by the Tangent^
that is, by a line parallel to the Horizon, and being that in the di-
urnal motion, if it be of the Earth, the Horizon goeth continually
deicending towards the Eaft, and rifing from the Weft (th<^refore
the Oriental Stars fcem to rife, and the Occidental to decline) fo
that the Oriental mark would defcend below the aime , and there-
upon the fliot would fly too high, and the afcending of the Weft-
ern mark would make the (hot aimed that way range too low j fo
the Peece would never carry true towards any point h and for
^Hat experience telleth us the contrary, it is requilite to lay^ that
Earth is immoveable.

Simp L. ThcfearefolidTeafons, and fuch as I believe no man
can anfwcr.

S A. L V. Perhaps they are new U> you ^

S f M p Really they are and now I fee with how many ad-
mirable experiments Nature is pleafed to favour us, wherewith to
^ftus in the knowledge of the Truth. Oh 1 how exaftly one

truth

10^

This arntiment
is confirmed hjirvo
\hots totvards the

Southard towards

the North.

Ai},i it if like-
vfife confirmed hf
tive (hots tow'^rds
the Etifi , tO'
ifiards thsWefi.

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

a G

alil:^us

his Syfli

erne.

Copernicus hi4
fellowers ^re no:
w,v:d through ig-
norance of I hear'
gMmems on the O'
ther part.

Chriftianus Vur-
ftitius read certain
Le^;ires tofichitg
the opinion of Co-
pernicus, & rfhat
enfned thereupon.

The foUoveef! of
Copernicus were
all frfi- agairft-
that, opinion , but
the SeElators of
Atirtocle & Pco-
lomy, Ttvere rever
itf the other Jtdc,

truth agrceth with another, and all confpirc to render each other
inexpugnable 1

Sagr. Whatpity it i^ that Guns were not ufed in Ariftotks
age, he would with help of t!-iem have callly battered down ig-
norance, and fpoke without habitation of thele mundane points.

S A L V. 1 am very glad that thefe reafons are new unto you, that
io you may not reft in the opinion of the major part of Fl-npatr
//<r^/, who believe, that if anyone forfakes the Doftrind ofAri-
it isbecaufe they did not underftand or rightly apprehend
his demonftrations. But you may expefl: to hear of dther Novel-
ties, and you fhaU fee the followers of this neW Syftcme produce a-
gainft themlelves obfervations, experiences, and reafons i of farrc
greater force than thofealledged by Ari^iotU, Ftolomy, and other
oppofers of the fame conclufions,and by this means you (hall come
to afcertain your felf that they were not induced through want of
knowledge or experience to follow that opinion.

Sagr. It is requifite that upon this occafion I relate unto you
fomc accidents that befell mCj-ib foon as I firft began to hear fpeak
of thi. ne-wdoSrine. Being very young, and having fcarcely fi-
nifted my courie of Philofophy, which I left off, as being fet upon
other employments, there chanced to come into thefe parts a cer-
tain Foreigner of Koftock^^ whofe name, as I remember was Chri-
ftianm y nrftitim^ ^ioWowi:^ oi Copcrnicii<5, who in an Academy
made two or three Leftures upon this point, to whom many flock't
as Auditors i but I thinking they went more for the i^ovclty of the
fub)ea than otherwife, did not go to hear him : for 1 had conclu-
ded with my felf that that opinion could be no other than a folemn
madncfle. And queftioning fome of thofe who had been there I
perceived they all made a jeft thereof, execpt one , who told me
that the buiinelle was not altogether to be laugh't at, and becaufe
this man was reputed by me to be very intelligent and wary, I re-
pented that I was not there, and began from that time forward as
oft as I met with any one of the Cofcrmcan perfwafion,to demand
of them,if they had been alwayes of the fame judgment^, and of as
many as I exammed, I found not fo much as one, who told m? not
that he had been a long time of the contrary opinion, but to have
changed it for this, as convinced by the ftrength of the reafons pro-
ving the fame : and afterwards queftioning them, one by one , to
fee whether they were well polTeft of the reafons of the other fide^
1 found them all to be very ready and perfeft in them ^ fo that I
could not truly fay, that they had took up this opinion out of ig-
norance , vanity , or to flicw the acuteneffe of their wits. On the
contrary , of as many of the Peripatetic's ^nd Ptolomeans as I
have asked (and out of curiollty 1 have talked with many) what
pains they had taken in the Book o( Copernicji^ ^ I found very

few

13 I A LOG liE^ IL

fevv that had fo much as fuperficially pcrufcd it but of thdfe
whom, I thought, had underftood the lame , not one ; and more-
over, I have enquired amongft the followers of the feripatetiek^^
DoSrine ^ if ever any of them had held the contrary opinion, and
Hkewile found none that had. Whereupon confidering that there
wa? no man who followed the opinion of Copernicus , that had
not been firft on the contrary fide , and that was not very well ac-
quiinted with the realonsof Ariftotle 2in^?tolo7ny', and, on the
Contrary , that there is not one of the followers of ?tolomy that
hid e\lerbeenof the judgment of Copernicus^ and had left that,
to imbrjice^ this of Ariflotle , confidering, I fay, thefe things, I
began to tliink , that one, wholeaveth an opinion imbued with
his milk^ and followed by very many , to take up another. owned
by very few , and denied by all the Schools , and that really
ieerfis a Very great Paradox , muft needs have been moved , not
to fay forced , by more powerful reafons. For this caufe, 1 ain
become very curious to dive , as they fay, into the bottom of this
bufinefle , and account it my great good fortune that I have met
you two from whom 1 m.y without any trouWe , hear all that
hath been, and, haply, can be faid on this argument , aflbnng
rnyfelf fha:rthe ftrengthof your teafons will reiolve all Icruples,
and bring me to a certainty in thi^ hibjeft. - •

S I M V L. But its poflible your opinion and hopes may btdih^-
pointed , and that you may find your felves more at a \oSc iti the
end than you was at firft.

S A G R. 1 am very confident that this can in no wife befal
me.

S I L* And why not > 1 have a manifeft example in my fclf,
that the farther 1 go , the more I am confounded.

S A G H. This is a fign that thofe reafons that hitherto feemcd
concluding unto you, andaffured you in the truth of your opi-
nion , begin to change countenance in your mind , and to let you
by degrees, if not imbrace, at leaftlook towards the contrary te-
ncnt brit I, that have been hitherto indifferent , do greatly hope
to acquire reft and fatisfafiion by our future difcourfes , and you
will not deny but I may, if you pleafe but to hear what perfwa-
deth me to this expeSation. , , ,

' S I M P 1,. I will gladly hearken to the fame , and ftould be no
Wife glad that the like effbft might be wrought in me.

S^ Gi.. Favour me therefore with anfwering to what I fliall ask
And firft, tell me, Stmpltcius , is not the conclufion, which
we feek the truth of, Whether we ought to hold with ArtftotU
^ndffoU^y ^ that the Earth onely abiding without motion in the
Centre of thcUniverfe, theCoeleftial bodies all move , orelle,
Whether the Starry Sphere and the Sunftanding ftiU in the Centre^

Motion Andrefl
prtftcipsl Mccidents
iummure*

Vntrmht cdnnot
be demonBrated ,
4U Truths are.

Tor proof of trH*
cone I tt /torn , manjr
folid drgttmettt s
may be produced,
but to proi^e 4
ptyy none*

G. GhLiL RKiSybis Sjfleme.

the Earth is without the fame^and owner of all thofe motions that
in our feeming belong to the Sun and fixed Stars ?

S I M p L. Thefe are the conclufions which are in difpute.

Sagr, And thefe two conclufions, are they not offuch a na-
ture, that one of them muft ncceffarily be true , -and the other
falfe ?

S I M p L. They are fo. We are in a Dilemma^ one part of which
muft of neceffity be true, and the other untrue y for between Mo-
tion and Reft, which are contradifiories, there cannot be inftanced
a third, fo as that one cannot fay the Earth moves not, nor ftands
ftill j the Sun and Stars do not move, and yet ftand not ftill.

S A G R. The Earth, the Sun, and Stars, what things are they in
nature > are they petite things not worth our notice, or grand and
worthy of confideration ? ^

Simp They are principal, noble, integral bodies of the Uni-
verle, moft vaft and confiderable.

S AGR. And Motion, and Reft, what accidents are thev ini
Nature i ^ j

S I M p L. So great and principal, that Nature her felf is defined
by them.

S A G R. So that moving eternally, and the being wholly immo-
veable are two conditions very confiderable in Nature and indi-
cate very great diverfity and efpecially when afcribcd to the
principal bodies of the Univerfe, from which can enfuc none but
very different events.

S I M p L. Yea doubtleffc.

S A G R. Now anfwer me to another point. Do you believe that

i^'/'i ' R/^e.fc^ric^, the P hy fields Metaphyfuks, Mathcmatickj,
and finally, m the univerfahty of Difputations there are arguments
fufficient to perl wade and demonftrate to a perfon the fallacious
no leffe then the true conclufions ? '

S I M p L. No Sir j rather I am very confident and certain that
for the proving of a true and neceffary conclufion, there are in
natwenotonelyone, but many very powerfuH demonftrations :
and that one may difculTe and handle the fame divers and fundry
waycs, without ever falling into any abfurdity and that the more
any Sophift would difturb and muddy it, the more clear would it5
certainty appear : And that on the contrary to make a falfe pofi-
tionpaffefortrue, andtoperfwade the belief thereof, there can-
not be any thing produced but fallacies, Sophifms, Paralogifmes>
t-quivocations, and Difcourfes vain, inconfiftant, and full of re-'
pugnanccs and contradiaions.

S A G R. No^Y eternal motion, aiki eternal reft be fo princi-
pal accidents of Nature, and fo difFerertt,^that there can depend
on them only moft different confequencc., and efpecially when

applied

D I A L O G U E I !• II3

applycd to the Sun , and to the Earth , fo vail and famous bodies
ot the Univcrle ^ and it being, moreover, impoffible , that one of
two conciadictor^ Pfopofitions, (hould not be true , and the other
falle i and that for proof of the falfc one , any thing can be pro-
duced but fallacies ^ but the true one being perfwadcable by all
kind of concluding and demonftrative arguments, why (hould
you think that he , of you two , who fliall be fo fortunate as to
maintain the true Propofition ought not to perfwade me ? You
muft fuppofc me to be of a ftupid wit , perverfe judgment , dull
mind and intellca, and cf a blind reafon , that 1 (hould not be
able to diftinguifli light from darkneiTe , jewels from coals , or
truth from faUhood.

-v/Sr^ ^l p L. I tell you now , and have told you upon other
occafions , that the beft Mafter to teach us how to difcern So-
phifmes Paralogifmes , and other fallacies , was Artfiotlc^ who
in this pal ticular can never be deceived.

S A G R.. Youinfift upon Ariliotle , who cannot fpeak. Yet I
tell you 5 that if Ariflotle were here , he would either yield him- AiiHotle woW^
felf to be perfwaded by us , or. refuting our arguments , convince "^^ZfZ!^s''ar^H'
us by better of his own. And you your felf , when you heard the tZsT" ZfnU
experiments of the Suns related, did you not acknowlcdg and ^'^'^ hts o^u^ton.
admire them, and confefl'e them more concludent than thole of
Ariftotle > Yet neverthelelfe 1 cannot perceive that Sal'uititHs ^
who hath produced them , examined them , and with exquifite
care fcan'd them , doth confefTe himfelf perfwaded by them \ no
nor by others of greater force , which he intimated that hewa»
about to give us an account of. And I know not on what grounds
you (hould cenfure Nature , as one that for many Ages hath
been lazie , and forgetful to produce Ipeculative rvits h and
that knoweth not how to make morefuch , unleffe they be fuch
kind of men as flavi(hly giving up their judgments to ArifiotUy do
underftand with his brain , and refent with his fenfes. But let us
hear the refidue of thofe reafons which favour his opmion, that
We may thereupon proceed to fpeak to them j comparing and
weighing them in the ballance of impartiality .

S A L V. Before I proceed any farther, I muft tell Sagredus^ that
m thefe our Difputations , I perfonate the Cofernican , and imi-
tate him, as if I were his Ztf«ry i but what hath been efFefted in
private thoughts by thefe arguments which 1 feem to alledg in
his favour , I would not have you to judg by what 1 fay , whiTft

^y my difguife , for you may chance ^^^^ different
irom what you fee me upon the Stage. Now Iclfe go on.

~j — luc u^\-»ii LUC oiage. x^-^"

tU followers produce another cxperhncnt hkc to

^hatot the Projeaions, and it is of things that

being feparated
from

Aft arj^ftmert
takf» from the
Cloutls y aadfr^itl^
Birds.

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

114

Argument
taken from the air
rvhicb vee feel to
heAt upon u-i rvhen
vpernna Horfe At
fmllfpced.

^» Argumint
taken from the
nhirling of (tret:"
I AY motion^ xchtch
hAth a f Acuity to
extrude And dijfi"
pAte,

G. G A L 1 L iE u s, his S'yjleme.

from the Earth , continue a good ipaceof time in the Air , fuch
?.s*'c the Clouds, Birds of flight; and a. of them ,t cannot be
faid'that they are rapt or tranfparted by the Earjh , having no ad-
hefion thereto , it leems not poffible , that they Oionld be able to
keep pace With the velocity thereof ; nay it (hould rather ieem
to us that they all fvviftly move towards the Weft : And it
being'carried about by the Earth , paffe our parallel m twenty
four hours , which yet is at leaft fixteen thoufand miles , how can
Birds follow luch a cdurCe or revolution ? Whereas on tlie con-
trary , wcfte them fly as well towards the Eaft , as towards the
Weft, or any other part , without any fenfible difterencc. More-
over if when we run a Horfe at his Ipeed , we feel the air beat
vehemently againft outface, what an impetuous blaft ought we
perpetually to feel from the Eaft , being carried with fo rapid a
cbiii-fe againft the wind ? and yet no fuch efteft is perceived. Take
another very ingenious argument inferred from the following ex-
periment. The circular motion hath a faculty to extrude and dif-
lipate from its Centfe the parts of the moving body , whenfoever
either the motion is rot very flow , or thote parts are not very
well fafteued togetlwr i and therefore , if c/.^. we fliould turn
one of thofe great wheels very faft about , wherein one or more
men walking , crane up very gi^at weights , as the huge maffie
ftone ufed by the Callander for prefluig of Cloaths ; or the
f ■ hted Barks which being haleid on fliore , are hoifted out of
Jne^rivcr into another i in cafe the parts of that fame Wheel fo
fwiftly turn d round , be not very well joyn'd and pind together,
they would all be ftiattered to pieces i and though many ftones or
other ponderous fubftances,{hould be very faft bound to its outward
Rinimc , yet could they net refift the impetuofity , which with
great violence would hurl them every way far from the Wheel,
and confequcntly from its Centre. So (hat if the Earth did move
with fuch and fo much greater velocity , what gravity, what tena-
city of Kmc or plaifter would keep together Stones, Buildings, and
whole Cities , that they (hould not be toft into the Air by (o pre-
cipitous a motion ? And both men and beafts , which are not fa-
ftened to the Earth , how could they refift fo great an impetni ?
Wherea-^ on the other fide , we fee both thefe , and far lefl"e re- L
fiftancesof peb'-cs , fands, leaves reft quietly on the Earth, and f
torctura to it in foUi^g , though with a very flow motion- Sec
W, Stmplicim, the moft potent arguments, taken, to folpeak,
from things Tcrreftrial i there remam thofe ot the other kind,
namely , fuchmhaVc relation to the appearances of Heaven,
which reafons,% confefi'e the truth , tend moro to prove the
Earth to be in the centre of theUniverfe, and confequcntly, to
deprive it of the annual motion about the fame , alcribed unto i«

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2°K.B. 9,163

D I A L o o a E IK

by Coper?ticm. Which arguments , as being of fomewhat a diffe-
rent nature , may be produced^ after we have examined the
ftiength of thefe already propounded.

S A G W hat fay you Simplicim ? do you think that Salviafus
is Mailer of, and knowcth how to unfold the FtolomeamnA Ari-
fiotelian arguments ^ Or do you think that any Peripatetic/^^ is e-
qually vcrft in the Coperjucan dcmonfti ^itions }

S I M p L. Were it not for the high eftccm, that the paft diicour-
fes have begot in me of the learning of Sal^iatm^ and of the a-
cutencflb oiSagredus , I would by their good leave have gone my
way without ftaying for their anlwers j it fecming to me a thing
impoflible , that fo palpable experiments fhould be contradifted^
and would, without hearing them farther , confirm my felf in my
old perlwafion ^ for though I (hould be made to fee that it was er-
roneous, its being upheld by fo many probable reafons, would ren-
der it excufeable. And if thefe are fallacies, what true demonftra-
tions were ever fo fair ?

, S A G R,. Yet its good that we hear the refponfions of Sal^iatus'y
which if they be true, muft of ncccflity be more fair, and that by
infinite decrees h and thofc muft be deformed, yea mofi deformed,
if the Metaphyfical Axiome hold, That true and fair are one and
the fame thing i as alfo falfe and deformed. Thotciorc Sal^zfiatus
let's no longer lofe time.

Sal v. The firft Argument alledged by SimpliciuSyii 1 well re-
member it, was this. The Earth cannot move circularly, bccaufe
fuch motion would be violent to the fame , and therefore not per-
petual : that it is violent, the reafon was ; Becaufe5that had it been
natural, its parts would likewife naturally move round , which is
impoffible, tor that it is natural for the parts thereof to move with a
right motion downwards. To this my reply is, that I could glad-
ly wifli, that AriflotU h2id more clecrly exprcft himfelf , where he
fa id j That its parts would likewife move circularly h for this mo-
ving circularly is to be underftood two wayes , one is, that every
particle or aiome feparated from it^ Whole would move circularly
about its particular centre, defcribing its fmall Circuletsj the other
IS, that the whole Globe moving about its centre in twenty four
hours 5 the parts alfo would turn about the fame centre in four and
twenty hours. The firft would be no le^^e an impertinency , than
if one fhould fay, that every part of the circumference of a Circle
^Jight to be a Circle •, or becaufe that the Earth is Spherical , that
therefore every part thereof be a Globe , forfo doth the Axiome
requue : Eadem eji ratio totim^ ^ parttunt^ But if he took it in
the other Icnfe , to wit, that the parts in imitation of the Whole
Ihonldmove naturally round the Centre of the whole Globe in
twenty four hours, i lay, that they do fo \ and it concerns you.

115

True and fair
are one and the
fame^ as alfo falfe
and deformed*

The anfwer t»

Arli\odcs firjl- at-
gHmer.t,

P 2

ftcad

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2°K.B. 9,163

That which if
violent ^ cannot be
eternal t And that
vfhich cannot he e-
ternal y cannot be
natural.

G. G A L I L ai: u s, his Syfleme.

inftead of Anjiotle , to prove that they do not.

S r M p L. This is proted by Anjiotle in the fame place, when he
faith, that the natural motion of the parts is the right motion
downwards to the centre of the Univerfc *, fo that the circular
motion cannot naturally agree therewith.

S A L V. But do not you fee, that thofe very words carry in them
a confutation of this folution ?

S I M p I. How ? and where ?

S A L V. Doth not he fay that the circular motion of the Earth
would be violent ? and therefore not eternal ? and that this is ab-
furd, for that the order of the World is eternal ?

SiMPL. He faith fo.

S A L V. But if that which is violent cannot be eternal , then by
converfion, that which cannot be eternal, cannot be natural : but
the motion of the Earth downwards cannot be otherwife eternal?
therefore much \c& can it be natural : nor can any other motion
be natural to it, fave onely that which is eternal. But if we make
the Earth move with a circular motion, this may be eternal to ic^
and to its parts, and therefore natural.

S I M p L. The right motion is moft natural to the parts of
Earth, and is to them eternal , nor (hall it ever happen that they
move not with a right motions alwayes provided that the impe-
diments be removed.

S Ai. V. You equivocate SimpliciHS i and I will try to free yoti
from the equivoke. Tell me , therefore, do you think that ^
Ship which (hould fail from the Strait of Gibralter towards FaU'
jkina can eternally move towards that Coaft ? keeping alwayes afl
equal courfc ^

S I M p L. No doubtlelTe.

Sal v. And why not?

S I M p L. Becaufe that Voyage is bounded and terminated be-
tween the Herculean Pillars, and the fliore of the Holy4and j and
the diftance being limited, it is paft in a finite time, unlelTe one by
returning back fliould with a contrary motion begin the fame Voy
age anew i but this would be an interrupted and no continued
motion.

Sai,v. Very true. But the Navigation from the Strait of M.
galanes by the Pacifick Ocean, the Molkcchas^ the Cape di bno
Sferan^U:, and from thence by the fame Strait, and then again b
the Pacifick^ Ocean, &c. do you believe that it may be perj
tuated ?

SiMvi. It may ^ for this being a circumgyration, which r
turneth about its felf, with infinite replications, it may be perpctU'
ated without any interruption.

S A I y. A Ship then may in this Voyage coatinuc failing eter-
nally* S I M F I.-

D I A L a£5 U E. I L

Si m r L. It may, in cafe the Ship were incorraptible, but the
Ship decaying, the Navigation mult of neceflity come to iin i?hd.
( ( S A L V. But in the Mediterranc, though the Veffel wereincor-
n^ptible, yet could (he not fail perpetually towards Fa\eflink\ thkt
Voyage being determined. Two things then are required, to the
end a moveable may without intermiflion move perpetually j the
one is, that the motion may of its own nature be indeterminat^e and
inhnite V' the other, that the moveable be likewifc incorruptible
and cternsfeli

S I M p ,u All this is necelfary .

bALv. Therefore you may feehow of your own accord j6tx
have confclTed it impoffible that any moveable (hould move Eter-
nally in a right line, in regard that right motion , whether it be up-
wards, or downwards, is by you your felf bounded by the circum-
ference and centre h fo that if a Moveable , as fuppofe the Earth
be eternal, yet forafmuch as the right motion is not of its own na-
ture eternall, but moft * terminate, it cannot naturally fait with
the Earth. Nay, as was faid * yeftcrday, Ariftotle himfdf h
conftrained to make the Tcr reft rial Olobe tternarlly imtrtbvt^b!^.
When again you fay, that the parts of the Earth evermdrd rf^bve
downwards, all impediments being fettioved, you egregioufly c^qui-^
vocate ; for then, on the other fide they mult ht impeded, contta-
ricd, and forced, if you would have them move \ for , wheri they
are once fallen to the ground, they muftbe violently thrown up-
wards, that they may a fecond time fall \ and as to the inipedi*
ments, thefe only hinder its arrival at the centre*, but if there \Vert
a IV ell^ that did paffc thorow and beyond the eentrejyet would not
aclod of Earth paffe beyond it, unleffe inafmuch as being tranf-
ported by its impetm-, it (hould paffe the fame to return thither a-
g^in, and in the end there to refl. As therefore to the deferiding,
that the motion by a right line doth or can agree naturally neither
t^the Earthy nor to any other moveable , whifft the Univerfe re-
taineth its pcrfe(Ei: order, I would have you take no further paines a-
boutit,but (unleffe you will grant them the circular motion)
your bcfl way will be to defend and maintain their immobility.

S r M p L. As to their immoveableneffe , the arguments of Ari-
ftotle^ and moreover thofe alledged by your felf feem in my opini-
oti ncceffatily to conclude the fame, as yet j and I conceive it will
a hard matter to refute jthem.

S A L V. Come we therefore to the fecond Argument, which was,
* hat thofe bodies, which we are afTured do move circularly, have
i^^re than one motion, unleffe it be the Frimum Mobile-^ and
therctore, if the Earth did move circularly, it ought to have two
motions^ from which alterations would follow in the rifing and
^tmg of the FiKed Star^ : Which cfFea is not perceived to cnfue.

There-

"'7

Tveo things rC"
quifite to the end a
motion mAj per-
pet Hate it felf; an
Hnlimited fpace ,
and An incorrnpti-
ble moveable.

%J,ght motion
cannot be eternal^
and coyfequently
cannot be natural
to the Earth,

* Terminaciffimo.

* By this exprtffi-
on he every where
means tlic prece-
ding Dialogue, or
^ tarn at a.

The An f veer t9
^he fecond ir^H"

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2°K.B. 9,163

• Subdcficcre.

Oi Ctntre.

Ariflotlcs4<rj^#»-
jnent sg<^i»fl' tht
Mart hi motion', is
deft^tve in tjvo
things.

* The fame word
which a littleabov^
Itcndred ft ay be-
hind 5 as a bowlc
when it meets wich

G. G A L 1 L iE u s , hk Sjfleme.

Therefore, &:c. The moft proper and genuine anfwer to this Alle-
gation is contained in the Argument itlelf j and even AriUoth
puts it in our mouths, which it is impoflible, SimplUim , that you
fhould not have feen.

S I M p L. I neither have feen it, nor do 1 yet apprehend it.
S A L V. This cannot be , fure , the thing is fo very plain.
S I M P L. I will with your leave , caft an eye upon the text,
S A G R. We will command the Text to be brought forthwith.
S I M p L. 1 alwayes carry it about with mc : See here it is , and
I know the place perfeftly well , which is in lib. a. Dt Ca^lo^ cap.
1 6. Here it is , Text 97. Freterea omnia , quje fernntHr latione
circnUri fubdeficere 'videntnr , ac mo<veri flitrihii^ itna latione^
fr<£ter primam Sph^ram h quare ^ Terr am necejfariam efl , fi^ve
circa medium , [1*2^^ in^ medio pofeta feratur , dnahns moifcri
lationibus. Si antcm hoc acciderit , necejfanam eji fieri mnta'
tiones ^ ac coni/erfiones fixomm afirorum. Hoc antem non^z/ide-
tnr fieri , Jed femper cadem , apnd eadem loca ipftus , ^ orinn*
tur ^ ^ Occident. [In Englifli thus : ] Furthermore all that are
carried with circular motion , feem to * foreflow , and to move
with more than one motion, except the firft Sphere 5 wherefore
it is neceffary that the Earth move with two motions, whether
it be carried about the * middle , or placed in the middle. Bpt
if it be fo , there would of neceflity be alterations and converfl-
ons made amongft the fixed Stars. But no fuch thing is feen to
be done , but the fame Star doth alwayes rife and fet in the fame
place. In all this I find not any falacy , and my thinks the argu-
ment is very forcible.

S A L V. And this new reading of the place hath confirmed uic
in the fallacy of the Sillogifme , and moreover , difcovered ano-
ther falfity. Therefore obi erve. The Pofitions , or if you willj
Conclufions , which Ariflotle endeavours to oppofe, are two j on
is that of thofe , who placing the Earth in the midft of the World,
do make it move in it felf about its own centre. The other is of
thofp , who conflituting it far from the middle , do make it re-
volve with a circular motion about the middle of the Univerfe.
And both thefe Pofitions he conjointly impugneth with one and
the fame argument. Now I affirm that he is out in both the one
and the other impugnation ^ and that his error againft the firft
Pofition is an Equivoke or Paralogifme \ and his miftake touch-
ing the iecond is a falfe confequence. Let us begin with the firft
Affertlon , which conftituteth the Earth in the midft of the
World, andmaketh it move in it felf about its own centre j and
Ictus confront it with the objeftion of AriftotU'-i faying, All
moveables , that move circularly , feem to * foreflow , and move
with mpre, than one Byas , except the firft Sphere (that is theprt-

I A L C G U E.

il.

WHm mobile^ thcixtore rhe Earth moving about its own centre,
being placed in the middle , muft of nccefliry have tw^o byafles,
and foreflow. But if this were fo , it would follow, that there
ftiould be a Variation in the riling and ferting of the fixed Stars ,
which we do not perceive to be done : Therefore the Earth doth
not move, Here is the Paralogifme, and ro difcover it, 1 will

argue with Ariptle in this manner. Thou faift , oh Anflotlc^
that the Earth placed in the middle of the World , canbot move
m it felf (i, e. upon itsown^xi5) for then it would beiequifite
to allow it two byaffes ^ fo that, if it fhoald not be neceiiary to
allow it more than one Byas onely , thou wonld^'ft not then hold
4t impoflii^l<: f^r it to move oncly with that one r F6r thou W'ould*^ft
unneceflarily have confined the impoflibility to the pkirality of
byaffes , if iii cafe it had no more but one , yet ft could not move
with that. And becaufe that of all the moveiiibtcs in the World,
thou makeft but one &lonc to move With oiie folebyas , and all
the reft with more than Oiie ^ and this fame moveable thou af-
firmeft to be the firft Sphere , namely , that by which all the fix-
ed and erratick Stars it:em harmortibiifly to move from Eaft to
Weft , if in cak the Earth may be that firft Sphere , that by iho-
ving with one byas onely , may make the Stars, appear to move
from Eaft to Weft , thou wilt not dfny them it : But he that iif-
firmcth, that the Earth being placed in the tnidft of the World,
moveth about its own Axis , afcribes unto it tio other motionj
fave that by which all the Stars appc-atto move from Eaft to Weft',
and fo it coir.ech to be that firft Sphere , which thou thy fclf ac-
knowledgeft to move with but one byas otiely. It is therqfore ne-
ceflary , oh Artflotlv , if thou wilt conclude any thing , that thou
demonftrace , that the Earth being placed in the midft of the
World 3 cannot move with fo much as one by a? onely', or elfe,
that much leffe can the firft Sphere have one fole motion ; for o-
therwife thou docft in thy very SiUogifme both commit the falacy,
anddeteftic, denying, and at that very time proving the fame
thing. 1 come now to the fecond Pofition , namely, of thofe
who placing the Earth far from the midft of the Univerfe , make
it moveable about the fame *, that is, make it a Planet and erra«
rick Star ^ againft which the argument is dire£lcd , and as to
form is concludent , but faileth in matter. For it being granted,
that the Earth doth in that manner move , and that with two by-
?ffes , yet doth it not neccfiarily follow that though it were fo,
^ould make alterations in the rifings and fettings of the fixed
\A\ ' * proper flace declare. And here I could

gladly excufc Anfiotlc \ rather I could highly applaud him for ha-
ving light upon the moft fubtil argument that could be produced
Againft the Copernicaii Hypothefes j and if the ob)e£i:i6n be inge-
nious^

ii9

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

Q G

A L I L iEU S

his SyfJi

erne.

the third
went.

The anfwer to
fhe fourth 4rgH*

nious, and to outward appearance moft powerful, you may fee
how much more acute and ingenious thefolution muft be , atiJ
not to be found by a wit leffe piercing than that of Copernicus ')
and again from the difficulty in undcrllanding it , you may argue
the fo much greater difficulty in finding it. But let us for the pic
fent fufpend our anfwer , which you (hall underftand in due time
and place , after we have repeated the objection of Anjiotley an^l
that in his favour , much ftrengthened. Now pafTe we to Art-
The dufvfer to jlotUs third Argument , touching which we need give no farther
MrgH' j.^p|y ^ jj. having been fufficiently anfwercd betwixt the dilcourfes
of yefterday and to day : In as much as he urgeth , that the mo-
tion of grave bodies is naturally by a right line to the ctntre j ani
then cnquireth , whether to the centre of the Earth , or to that
of the Uiiiverfe, and concludeth that they tend naturally to the
centre of the Univerfe , but accidentally to that of the Earth.
Therefore we ^T^ay proceed to the fourth , upon which its requifite
that we ft ay fome time , by reafon it is founded upon that expc
riment , from whence the greater pare of the remaining argu-
ments derive all their ftrength. Arijiotle faith therefore / that it is
a moft convincing argument of the Earths immobility , to fee
that projeftions thrown or (hot upright , return perpendicularly
by the fame line unto the lame place from whence they were {hot
or thrown. And this holdeth true , although the motion be of ^
very great height j which could never come to paffe , did the
Earth move : for in the time that the projefted body is moving
upwards and downwards In a ftate of feparation from the Earth?
the place from whence the motion of the projedion began, woul^l
be paft 3 by means of the Earths revolution, a great wav tO'
wards the Eaft, and look how great that fpacewas, fo far from
that place would the projeSed body in its defcent come to the
ground. So that hither may be referred the argument taken froi^
a bullet {hot from a Canon direfily upwards 5 as alfo that othef
ukd by Arifiotle zndPtolomy , of the grave bodies that falling
from on high , are obferved to defcend by a direfi and perpendicU'
lar line to the furfacc of the Earth. Now that 1 may begin to untie
thefe knots , I demand of SimfUcins that in cafe one fliould deny
to Ptolemy and AnjiotU that weights in falling freely from oi»
high , defcend by a right and perpendicular line , that is, direftly
to the centre , what means he would ufe to prove it ?

S I M p L. The means of the fenfes j the which alTureth us, that
^^at Tower or other altitude, is upright and perpendicular , ^ni
iheweth us that that ftone , or other grave body , doth Aide along
the Wall , without inclining a hairs breadth to one fide or anO'
ther, and light at the foot thereof juft under the place from whence
it was kt fall.

S A L Ve.

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2°K.B. 9,163

iri-
her

D I A L o G u E I L i:t

S A L V. But if it fliould happen that the Terreftrial Globe did
move round, and confequently carry the Tower aUb along with
It, and that the ftone did then alfo grate and Aide along the fide of
-he Tower, what inuft its motion be then ?

S I M p L. In this cafe we may rather fay its motions : for it
would have one wherewith to defcend from the top of the Tower
to the bottom, and (hould neceflarily have another to follow the
courle of the laid Tower.

S A L V. So that its motion fliould be compounded of two, to
wit, of that wherewith it meafurcth the Tower, and of that o-
ther wherewith it followeth the fame : From which compofition
would follow, tliat the ftone would no longer defcribe that fimple
right and perpendicular line, but one tranfverfe, and perhaps not
ftreight.

S I M p L. I can fay nothing of its non-reflitude, but this I know
very well,, that it would of neceffity be tranfverfe, and difterent
from the other direftly perpendicular, which it doth defcribe the
Earth ftandingftill.

S A L V. You fecj:hen, that upon the meer obferving the falline
ftone to glide along the Tower^ you cannot certainly affirm that
it defcribcth a line which is ftreight and perpendicular, unlefs you
firft fuppofe that the Earth ftaiideth ftill,

S I M p L. True , for if the Earth (hould move, the ftones mo-
tion would be tranfverfe, and not perpendicular.

S A L V. Behold then the Paralogifm of. Jnjiotle and Ftolomey n^Par.io.if.
to be evident and maniteft, and difcovercd by you your felf, of Ariftoile W
wherein that is iuppoled for known, which is intended to be de- P^^^^^^^y/'' fT
monftrated.

^ I M P L. How can that be ? To me it appeareth that the
Syllogilm is rightly demonftrated vi\i\\oMtpetitionem pnactpii.

S A L V. You fl)all fee how it is j anfwer me a little. Doth he
'^ot lay down the conclufion as unknown?

S I M p L. Unknown i why otherwife the demonft rating it would
be fuperfluous.

S A L V. But the middle term, ought not that to be known ?
S I M P L. Its necelfary that it fliould ; for otherwife it would be
a proving igmtHm per ^que ignotnm.

S A L V. Our conclufion which is to be proved, and which is ua-
known, is it not the ftability of the Earth ?
' ' ^ I M p L. It is the fame.

O ^ middle term, which ought to be knownjis it not the
"^^»&ht and perpendicular defcent of the ftone ?
^^f^v>L. Itisfo.

S A L y. But was it not juft now concluded, that we can have
no certam knowlcdg whether that fame fliall bedireft and perpen-

CL dicular,'

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2°K.B. 9,163

ttth thdt the Fire
moveth direUlj
upwards by na-
ture^ and round a'
bout bj parftcip/i-

G. G A L I L u s , his SjjJeme.

dicular, unlefs vvc fn ft know that the Earth ftands ftill ? Therefore
in your Syllogifm the certainty of the middle term is affumei
from the uncertainty of the conclufion. You may fee then, what
and how great the Paralogifm is.

S A G R. I would, in favour o{ Stmpltcius^ defend Anjlotle if it
were poflible , or at leaft better fatisfie my felf concerning the
ftrength of your illation. You fay, that the feeing the ftone rake
along the Tower, is not fufficient to affure us, that its motion
perpendicular (which is the middle term of the Syllogifm) unlefs
it be prefuppofcd, that the Earth ftandeth ftill, which is the con-
clufion robe proved : For that if the Tower did move together
with the Earth, and the ftone did Aide along the fame, the motion
of the ftone would be tranfverfe, and not perpendicular. But I
fliall anfwer, that fhould the Tower move, it would be impoffibk
that the ftone ftiould fall gliding along the fide of it , and there-
fore from its falling in that manner the ftability of the Earth is in-
ferred.

S I M p L. It is fo 5 for if you would have the ftone in defcend*
ing to grate upon the Tower , though it were carried round by
the Earth, you muft allow the ftone two natural motions, to wit,
the ftraight motion towards the Centre, and the circular about
the Centre, the which is impoflible.

Salv. 4rifiotUs defenfc then confifteth in the impoffibilitic
or at leaft in his efteeming it an impoffibility, that the ftone fliouI<^
move with a motion mixt of right and circular : for if he di<l
not hold it impoflible that the ftone could move to the Centre?
and about the Centre at once, he muft have underftood, that it
might come to pafs that the cadent ftone might in its dcfcent, race
the Tower as well when it moved as when it ftood ftill j and con-
fequently he muft have perceived, that from this grating nothing
could be inferred touching the mobility or immobility of the
Earth. But this doth not any way excufe AriUotle j afwtU be*
caufe he ought to have exprcft it, if he had had fuch a conceit, ti
being fo material a part of his Argument •, as alfo becaufe it cal»
neither be faid that fuch aneffcfi is impoflible, nor that Jrijiotk
didefluiiem it fo. The firft cannot be aflSrmed, for that by an<l
by I (hall (hew that it is not onely poflible, but neceflary : not
much lefs can the fecond be averred, for that Arijlotlc himfelf
granteth fire to move naturally upwards in a right line, and to
move about with the diurnal motion, imparted by Heaven to the
whale Element of Fire, and the greater part of the Air : If there'
fore he held it not impoflible to mix the right motion upward??
with the circular communicated to the Fire and Air from the con-
cave of the Moon, much lefs ought he to account impoflible the
mixtwe of the right motion downwards of the ftone, with the

circul»f

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2°K.B. 9,163

I A i 6 0 U E

ir:

bat

^^hole Terrcftrial

:h^

ibl^
ere-

itie,

circular which we prcfuppofe natural to tl
Globe, of which the ftone is a part.

Si M p L. I ice no fuch thing : for if the element of Fire re-
volve round together with the Air, it is a very eafie, yea a neceflary
thing, that a fpark of tire which from the Earth mounts upwards,
in pacing thorow the moving air, fhoukl receive the fame motion,
being a body fo thin, light, and eaiie to be moved : but that a
very heavy ftone, or a Canon bullet, that defccndcth from oa
high, and that is at liberty to move w^hither it will, fhouldfuffep
it'felf to^be tranfported either by the air or any other thing, h'
alrogethcf incredible. Beiides that, we have the Experiment,
which is fo jnopcr to our purpofe, of the ftone let fall from the
round top of the Maft of a {hip, which when the (hip lyeth ftill,-
fallcfh at the Parrnci s of che Maft v but when the (hip faileth, falfe
lo far dtftant from that place, by how far the (hip in the time of
the ftones falling had run forward which will not be a few fa*
thorns, when the fliips courfe is fwift.

S A L V. Tlterc is a great disparity between the caffe of the Ship
and that of the Earth, if the TcFreftrial Globe be fuppofed to have
a diurnal motion. F^^^ '^^ ^ thmg very manifeft:, tl>at the mo-
tion of the Ship, as it is notnatural to it, fo the motion of all thofe
things that arc in it is accidental^ whence it is no wonder that the
ftone wtxieh was retained in the round top, being left at liberty,
defcendeth downwards without g^ny obligation to follow chc mo-
tron of the Ship. But the diurnal converfios is afcribed to the
Terreftml Globe for its proper and natural motion, and Gonilc-
cjiTently, IP is fa to alhhe part^of thefaidGlobe •, and, as being
mrprcfs'd by nature, is indelible in them j and therefore that ftone
that h on the top of the Tower hath an intrinfick inclination of
revolving about the Centre of its IVhole in twenty four hours, and!
Afe feme natural inftinft it exereifeth eternally, be it placed in any
fete whatfoever. And to be affured of the truth of this, yoii
laave no more to do but to alter an antiquated impreffion made
ifi^ your mind ^ and to fay. Like as in that 1 hitherto holding it to
he the property of the Terrcftrial Globe to reft immoveable about
ka Centre, did never doubt or queftion but that all whatfoever
particles thereof do alfo naturally remain in the fame ftate of reft :
Soitis reafon, in cafe the Terrcftrial Globe did move round by
J^atnral inftiafl: in twenty four hours, that the intrinfick and natu-
inclination of all its pares fliould alfo be, not to ftand ftill, but
^ felk)w the fame revolution. And thus without running into
any inconvenience, one may conclude, that in regard the motion
conterred by the force of * Oars on the Ship, and by it on all the
lyings that are contained within her, is not natural but forreign, it
^ very reafonable that that ftone, it being fcparatcd from the (hip,

a_ 2 do

77v Aifparhy he'
tvfecH the fall of a
fione from the
roHnJi toy »f a fh'p,
and from the tof
of 4 tower.

'Time you may not
i"urpe(5i my rranfla-
cion, or woiuiet
whac Oars have to
do with a (hip, you
are to know that
[he Author intends
the Gallics ufed ia
the Mcdicerrane.

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2°K.B. 9,163

C. G A L I L i?: u s, his Syfleme.

do reduce its lelf to its natural difpofure, and return to exercifc
A^^\Xulr\' V^^^^ fimplc inftina given it by nature. To this I add, that
thl J$rmoJl lis necelTary, that at Icaft that part of the Air vvhich is beneath the
tatns doth foUoxP gj-^atcr heights of mountains, fliould be traniported and carried •
farZ"'" ^/ the S^^^j roughnefs of the Earths furfacc or that, as being

mixt with many ^Vapours, and terrene Exhalations , it do na-
turally follow the diurnal motion , which occurreth not in the
Air about the {hip rowed by Oars : So that your arguing
from the ftiip to the Tower hath not the force of an illation j
becaufe that ftone which falls from the round top of the Maft,
entereth into a vtedinm , which is unconcerned in the motion
of the fliip : but that which departeth from the top of the Tower,
finds a medium th^t hath a motion in common with the whole TcP
reftrial Globe ^ fo that without being hindred, rather being aflifted
by the motion of the air, it may follow the univerfal courfeof the
Earths

S I M p L. 1 cannot conceive that the air can imprint in a very
rhe^iotionofthe great ftone, or in a grols Globe of Wood or Ball of Lead, as
^htZhttlZZ fuppofe of two hundred weight, the motion wherewith its felf is
bHtnltt^^^^ moved, and which it doth perhaps communicate to feathers, fnow,
and other very light things : nay, 1 fee that a weight of that na-
ture, being expofcd to any the moft impetuous wind, is not therc'
by removed an inch from its place ^ now confider with your fcU
whether the air will carry it along therewith.

S A L V. There i%great difference between your experiment and
our cafe. You introduce the wind blowing againft that ftonC?
fnppofed in a ftate of reft, and we expofe to the air, which already
moveth, the ftone which doth alfo move with the fame velocity ?
fo that the air is not to conferr a new motion upon it, but onely
to maintain, or to fpeak better, not to hinder the motion already
acquired ; you would drive the ftone with a ftrangq and prcter
natural motion, and we defire to conferve it in its natural. \i
you would produce a more pertinent experiment, you fliould fay?
that it is obferved, if not with the eye. of the forehead, yet wilb
that of the mind, what would evene, if an eagle that is carried by
the courfe of the wind, fliould let a ftone fall from its talons?
which, in regard that at its being let go, it went along with the
•wind and after it was let fall it entered into a medium t\\2it mo-
ved with equal velocity, I am very confident that it would not be
leento defcend in its fall perpendicularly, but that following the
courfeof the wind, and adding thereto that of its particular gra'
vity, it would move with a tranfverfe motion.

S I M V I.. But it would firft be known how fuch an experiment
may be made ^ and then one might judg according to the event'
In the mean time the effeft of the fliip doth hitheuo inclii\c to fr'
vour our opinion. S a l ^'

I ALOGU E.

II.

^1 i

S A L V. Well laid yoa hitherto^ for perhaps it may anon change
countenance. And that 1 may no longer hold you in fuipenfe,
tell me, 5'/>/p//ri;^, do you really believe, that the Experiment of
the fliip fquares fo very well with our purpofe, as that it ought to
be believed, that that which we fee happen in it, ought alfo to
evene in the Terreftrial Globe ?

S I M p L. As yet 1 am of that opinion and though you have
alledged fomc fmall diiparities, I do not think tbem of fo great
moment, as that they (hould make me change my judgment.

Salv. I rather defire that you would continue therein, and
hold for certain, that the cfFe£i: of the Earth would exaftly anfwer
that of the fliip : provided, that when it fliall appear prejudicial to
your caufe, you would not be humorous and alter your thoughts.
You may haply fay, Forafmuch as when the (hip ftands ftill, the
ftonc falls at the foot of the Maft, and when (he is under fail, it
lights far from thence, that therefore by converllon, from the ftones
falling at the foot is argued the (hips (landing ftill, and from its
falling far from thence is argued her moving i and becaufe that
which occurreth to the fliip, ought likewife to befall the Earth :
that therefore from the falling of the ftone at the foot of the Tow-
er is neceflarily inferred the immobility of the Terreftrial Globe.
Is not this your argumentation ?

SiMPL. It is 5 and reduced into that concifenefs, as that it is
become moft eafie to be apprehended.

Salv. Now tell me j if the ftone let fall from the Round-
top , when the (hip is in a fwift courfe , (hould fall exaftly in
the fame place of the (hip, in which it falleth when the (hip is at
anchor, what fcrvice would thefe experiments do you, in order to
the afcertaining whether the ve(rel doth ftand ftill or move ?

S I M p L. Juft none : Like as, for exemple, from the beating of
the pulfe one cannot know whether a perfon be afleep or awake,
feeing that the pulfe beateth after the fame manner in (leeping as
in waking.

: S A L V. Very well. Have you ever trycd the experiment of the
Ship }

SiMPL. 1 have not ^ but yet I believe that thofe Authors
which alledg the fame, have accurately obferved it i be(ides that
the caufe of the difparity is fo manifcftly known, that it admits
of no queftion.

Salv. That it is poflTiblc that thofe Authors inftance in it,
Without having made tryal of it, you your fclf are a good tefti-
"^^«y> that without having examined it, alledg it as certain, and in
^ %^ki^'^^^ ^^^y ^^^'^ ^^^^^ authority as it is now not onely
poflible, but very probable that they likewife did j I mean, did
remit the lame to their Prcdeceflbrs, without ever arriving at one

that

ill

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2°K.B. 9,163

ii6

The IfoKe falliMg
from the Adalt of
a (hip lights in the
fame place , rvhe-
ther the (hip doth
wove or Ij fliH.

G. G A L I L B u s ^ his Sjdeme.

^hat had made the experiment : for whoever (hall examine the
fame, ftiall find the event fucceed quite contrary to what hath
been written of it : that is, heflialliee the ftone fall at all times
in the fame place of the Ship, whether it ftand ftill, or move with
any whatfoever velocity. So that the fame holding true in the
Earth, as in the Ship, one cannot from the ftones falling perpen-
dicularly at the foot of the Tower, conclude any thing touching
the motion or reft of the Earth.

Si M p L. if you fliould refer me to any other means than to
experience, I verily believe our Difputations would not come to
an end in haftc i for this feemeth to me a thing fo remote from all
humcinc reafon, as that it leaveth not the leaft place for credulity
or probability.

S A L y. And yet it hath left place in me for both.

S I M y L. How this ? You hav^ not made an hundred, no nor
one proof thereof, and do you fo conlideiuly affirm it for true I
I for my part will return to my incredulity, and to the confidence
I had that the Experiment hath been tried by the ppincipal Au*
thors whama4q afc .|herc;pf, amdi that thtieyent fucceedcd aa \
affirm^ .i - . -j. 7I • -Hj't ' <

S A K V. I am affured that the effefi will enfue as 1 tell yoti, for fi
it is neceffary that it Qiould : and I farther adBi^that you know yo '
felf that it cannot faiU out otfepcwife, howrvcir you feign or feem t
feign that you know it not. iY.^ I ana to good at taming of wit4
that I will makjc yoq cpnfcls th^'Iame whether you will or no. Bu
5"^^rc^/^*iy ftands very mute, a«id y«t, if li ralftike not, I faw h*
make ^ offer to fpei^ foiBewhajj.

S A G.ti. 1 had a,Ki intent to fay fosmcthing, but to tell you true,
know not whatit v^as^ fof theciuiixifity that you have moved in m
Jby promifing that you would focee Smplicim to difcover th
knowledg which he would coiw?eaJ feom u5y ha^th made me to de
pofe all other thoughts : therefofc I pray you to make good you
vaunt.

' ^-f) ^ ^* • P^^^idecJ 7 that SimplieiH^ do confent to reply to what
(hall ask him, I will not fail to do it.

S I M F L. 1 will anfwer whajt 1 know, affined that I fliall not be
much put to it, for that of thoCe things which 1 hold to befalfe,
I think nothing can be kupwn, ia regard that Science refpeSc:
truths and not fal (hoods.

S A L v. I defixe not that you fliould fay or reply, that you kno
^"^Y thing, fave that which you moft affiiredly know. Therefor
tell me If you had here a fkt fttperficies as polite as a Lookin
glafs, and of a fubftance as hard as fteel, and that it were not pa
cafcl to the Horizon, ^m- fomcwhat inclining, and that upon "
you didpi^tia BaU perfe% fphcrical, and of a. Hibftance grave a-

bar

I A L O G U E

;ut

nil

Wdj aj fuppofe of brats ^ what think you it would do being let
go ? do not you believe (zs for my pare I do) that it would lie
ftill?

S 1 M p L. If that fuperficies were inclining ?
S A L V. Yes-, for fo I have already fuppofed.
Sim PL. I cannot conceive how itftiouldlie fiill : nay, I am
confident that it would move tovvards the declivity with much pro-

S A L V. Take good heed what you fay, Sim^icins^ for I am
cpj^fident that it would lie ftill in what ever place you fliould lay

, Si 1^.1 8q long as you make ufe of fuch fuppofitions, SaU
<viatus^ J {hall ceai'e to wonder if you infefr moft abfurd con-
clufionsv : ; :

S A L V. Ate you 2^tir<;d, then, that it would freely move to-
wards the declivity ^,iv> :v

S I M p L. Who doubts it ?
; ^ S A L V. And this you verily believe, not becaufc I told you fo,
(for I endeavoured to perfwade you to think the contrary) biit of
your felf, and upon yonx natural judgment.

S I M p Now 1 fee what you would be at ^ you fpoke not this
as really believing the fame s but to try me, and to wreft matter
out of my own mouth wherewith to condemn me. • '

S A L V. Yqu are in the right. And how long would that Ball
move, and with what velocity ? But take notice that I inftanced
in a Ball exafily rounds and a plain exquifitely poliflicd, that all
external and accidental impediments might be taken away. And
fo wouI4 I have you remove all obftrudions caufed by the Airs re-
fi^^t^nce (;9 divifion, and all other cafual obftacles, if any other
Aere can be.

S I M p I,. I very well uiiderftaiad your meaning , and as to your
demand, I anfwer, that the Ball would continue to move in itu
fj^itum^ if the inclination of the plain Ihould fo long laft, and con-
imually with an accelerating motion i for fuch is the nature of
ponderous moveables, that *vires acqnirant eundo : and the great-

the declivity was, the greater the velocity would be.

S A L V. But if one fliould require that that Ball fliouId move
upwards on that fame fuperficies, do you believe that it would

SiMPL, Not fpontancoufiy 5 but being drawn, or violently
^^M^n, itmay. ^.[ aj m:

S A L V. And in cafe it were thruft forward by the impreffion of
lome violent impetus from withoqt, what and how great would
*ts motion be

S I M p L. The motion would go continually decreafing and re-

tardingT

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

G. G ALU BUS , his Sjfleme.

tarding, as being contrary to nature, and would be longer or
fliorter, according to tlie greater or lels impulfe, and according to
the greater or kl's acclivity.

S A L V. It feems, then, that hitherto you have explained to me
the accidents of a moveable upon two different Planes , and that
in the inclining plane, the grave moveable doth fpontaneoufly de-
fcend,andgoeth continually accelerating, and that to retain it in
reftj force muft be ufed therein : but that on the afcending planci,
there is required a force to thruft it forward, and alfo to flay it in
reft 5 and that the motion impreffed gocth continually diminiftiing?
till that in the end it comethto nothing. You fay yet farther
that in both the one and the other cafe, there do arife differences
from the planes having a greater or lefs declivity or acclivity h
that the greater inclination is attended with the greater velocity 7
and contrariwife, upon the afcending plane, the fame moveable
thrown with the fame force, movcth a greater diftance, by hovV
much the elevation is lefs. Now tell me, what would befall the 1
fame moveable upon a fuperficics that had neither acclivity nof
declivity '

S I M p L. Here you muft give me a little time to confidcr of an
anfwer. There being no declivity, there can be no natural incli'
nation to motion : and there being no acclivity, there can be i5o
refiftance to being moved ^ fo that there would arife an indiffe-
rence between propenfion and refiftance of motion ^ therefore?
inethijiks it ought naturally to ftand ftill. But I had forgot my
fel£ ; it was but even now that Sagredus gave me to undcrftand
jth^Vt it would fo do.

S A/L So I think, provided one did lay it down gently : bui
if it hadanwpeti^^ given it towards any part, what would f<^
low?

Simp. There would follow, that it Ihould move towards that
part.

Sal v. But with what kind of motion ? with the continually
-accelerated, as in declining planes j or with the fucceffively r^^
.tarded, as in thofe afcending.

Simp. I cannot tell how to difcovcr any caufc of acceleration')
or retardation, there being no declivity or acclivity.

Sal v. WeH : but if there be no caufe of retardation, much
lefs ought there to be any caufe of reft. How long therefore
would you have the moveable to move ?

Simp. As long as that fupcrficies, neither inclined nor decli-
nedChalUaft. :i

; S A L V. Therefore if fuch a fpace were interminate, the motioi*
upon the fame would Ukewife have no termination, that is, woul^l
be perpetual, ,y . ..

Si MP t»

D i A L O U F. it.

S i M p. 1 think ib , if fo be the moveable be of a matter
durable.

Sa L V. That hath been already fuppofed , when it was laid-,
that all external and accident:al impediments were removed , and
the brittieneffe of the moveable in this our cafe , is one of thbfe
impediments accidental. Tell me now, what do you think is the
caufc that that fame Ball moveth fpontaneoufly upon the inclining
plane, and not without violence upon the erefied >

Simp. Becaufc the inclination of grave bodies is to move to-
wards the centre of the Earth , and onely by violence upwards to-
wards the circumference , and the inclining fuperficics is that
which acquireth vicinity to the centre , and the afcending one,
remotencli'e.

/^ ^^Lv. Therefore a fuperficies, which fliould be neither de-
clining nor afcending , ought in all its parts to be equally di-
ftant fiom the centre. But is there any fuch fuperficies in the
World?

S I M p. There is no want thereof : Such is our TerreftriaA
Globe , if it were more even , rough and montai-

nous ^ but you have that of the Water , at fuch time as it is cahn
and ftill.

• S A L V. Then a (hip which moveth in a calm at Sea , is one of
thofe moveables , which run along one of thofe fuperficies that
arc neither declining nor afcending , and therefore difpofed, in
cale allobftacles external and accidental were removed, to move
with the impulfe once imparted inceffantly and uniformly.
SiMPL. It fliould feem to be fo.

S A L V. And that ftone which is on the round top , doth not it
i^ovc , as being together with thefliip carried about by the cir-
cumference of a Circle about the Centre ^ and therefore confe-
quently by a motion in it indelible , if all extern obftacles be
removed > And is not this motion as fwift as that of the fliip.
S I M p L. Hitherto all is well. But what followeth >
S A L V. Then in good time recant , I pray you , that your laft
conclufion , if you are fatisfied with the truth of all the pre-
mifes.

Simp l. By my lall conclufion , you mean , That that fame
ftone moving with a motion indelibly imprefled upon it, is not to
leave , nay lather is to follow the fliip , and in the end to light in
ielf fame place , where it faHeth when the fliip lyeth ftill and
1 alfo grant it would do , in cafe there were no outward impe-
diments that might difturb the ftones motion , after its being let
go , the which impediments are two, the one is the moveables
inability to break through the air with its meer impetus onely , it
^^ing deprived of that of the ftrengthof Oars , of which it hacl

ii9

beer^

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J G. G A L I L ^ u s , his SjfJeme.

been partaker , as part of the (hip , at the time that it was upon
the Maft , the other is the new motion of delcent , which alfo
muft needy be an hinderance of that other progrefiive morion.

S A L V. As to the impediment of the Air , I do ftot deny it
youj and if the thing falling were a light matter, asafeather,
Of a lock of wool, the retardation would be very great, butirt
an heavy ftone is very exceeding fmall. And you your felf but
even now did fay , that the force of the moft impetuous wind
fufficeth not to ftir a great ftone from its place i now do but con-
fiderwhat the calmer air is able to do, being cncountred by a
ftone no more fwift than the whole fliip. Neverthelefle , as I fai^
before , I do allow you this fmall eft'efl:, that may depend up
fuch an impediment like as 1 know , that you will grant to m
that if the air fhould move with the fame velocity that the (hi_
and ftone hath , then the impediment would be nothing at all-
As to the other of the additional motion downwards , in the firft
place it is manifeft , that the fe two , I mean the circular, about
the centre 5 and the ft/eight , towards the centre , are not contra-
"ries, or deftruflive to one another, or incompatible. Becaufe tha^
as to the moveable , it hath no repugnance at all to fuch motions,
for you your felf have already confeft the repugnance to be a-
gainft the motion which removeth from the centre , and the inch*
nation to be towards the motion which approacheth to the centt^'
Wheucc k doth of neceflky follow , that the moveable hath nei-
ther repugnance , nor propenfioh to the motion which neither ap'
pioacheth , nor gocth from the centre , nor confequently is there
any caufe for the diminifliing in it the faculty impreffed. And for-
afmuch as the moving caufe is not one alone , which it hath at'
tained by the new operation of retardation , but that they af^
two y diftind from each other , of which, the gravity attends on'
ly to the drawing of the moveable towards the centre , and thC
vertue imprefst to the conducing it about the centre , there r^*
maineth no occafion of impediment.

S I M p L. Your argumentation , to give you your due , is vcrjf
probable h but in reality it is invellopcd with certain intricacies?
that are not eafie to be extricated. You have all along built upo/»
The projta ac a fuppofitioH , which the Terifatetkk^ Schools will not eafily grant
cordtrig to Ar fto- ^ he\n^ direSlv Contrary to Arilioth , and it is to take io^

Jrt.c fmprejf.d, known and manifeft , That the projeft feparated from the projf
^Ht^jithctxitdmn^. c\^^^^ continueth the motion by vertue impreffed on it by th^
(aid projicient » which 'Z/erJwe imfrejfed is a thing as much det^"
ftcd \xx Perzpamuk^ Philofophy 5 as the paflage of any accidenj
from one fubiefl: into another. Which dofirine doth hold , as I
believe it is well known unto you , that the pro)e£l: is carri ed bf
the medium ., which ia out cafe happencth to be the Air. Ao^

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fre.

for-

Dialogue. II. i}i

therefore if that ftoiic let fall from the round top , ought to fol-
low the motion of the fliip , that efFeft fliould'be afcribed to the
Air, and not to the vcrtue impreffed. But you prefuppofe that
the Ail doth not follow the motion of the (hip , but is tranquil.
Moreover, he that letteth it fall ^ is not to throw it , or to give
it impctm with his arm , but ought barely to open his hand and let
it go and by this means , the Hone , neither through the vertue
imprelTcd by the proficient , nor through the help of the Air, •
(hall be able to follow the fliips motion , and therefore fliall be
left behind.

S A L V. I think then that you would fay , that if the ftone be
not thrown by the arm of that perfon , it i? no longer a pro-
jefiion.

S I M p L. It cannot be properly called a motion of projeftion.
S A L V. So then that which Arijiotle fpeaks of the motion, the
moveable , and the mover of the projefts , hath nothing to do
with the bufincffe in hand ^ and if it concern notour purpofcj
why do you alledg the fame ?

S I M V. I produce it on the oceafion of that impreffed vertue,
named and fntroduced by you , which having no being in the
World , can be of no force *, for non-enttHm nnUdt junt oferatio-
nes ; and therefore not onely of projeftcd , but of all other pre-
ternatural motions , the moving caufc ought to be afcribed to the
medium , of which there hath been no due confideration had 5
and therefore all that hath been faid hitherto is to no purpofe.

S A L V. Go to now , in good time. But tell me , feeing that
your inftance is wholly grounded upon the nuUity of the vertue
impreffed , if I (hall demonftrate to you, that the medium hath
nothing to do in the continuation of projefts, after they arc fc-
patated from the proficient , will you admit of the inaprefTed ver-
tue , or will you make another attempt to overthrow it >

Simp. The operation of the medium being removed , I fee not
how one can have recourfe to any thing elfc fave the faculty im-
preffed by the mover.

Salv. It would be well, for the removing, as much as is
poCTible , the occafions of multiplying contentions , that you
Would explain with as much diftinancffe as may be , what is that
operation of the medtnm 'm continuing the motion of the pro,ea J?^;;;^;^

Simp. The proiicient hath the ftone in his hand , ana with ^f^^
force and violence throws his arm , with which jaaation the rh. pr.j.^.
ftone doth not move fomuch as the circumambient Air ^ lothat
when the ftone at its being forfaken by the hand , findeth it felf
in the Air , which at the fame time moveth with impetoufity , it
15 thereby born away ; for, if the air did not operate , the ftone
Would fall at the foot of the proiicient or thrower.

R a Sa«.V.

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G. G A L I L iE u s , his Syjleme, ^

r.»r;;; J,^ "^.^^ ^^^'^^'o"^ . to futFer yom- fclf to be

<.^.»;f Pertwadedto believe thefe fopperies , fo long as you had your
riVivt'"! . u W/<>nfute them , and to underftand the

fiJX^. '^"'h '^I'^^f ^ Therefore tell me, that great ftone , and that
Canon bu let, which but onely laid upon a table, did continue
immoveable agamft the moft impetuous winds , according as you a
httk before didaffirm , if it had been a ball of cork or other light
itulte, think you that the wind would have removed it from its
place ?

Simp. Yes, and I am affured that it would have blown it
quite away , and with fo much more velocity , by how much the
matter was lighter, for upon thisreafonwe fee the clouds to be
tranfported with a velocity equal to that of the wind that drives
tiicm.

S A L V. And what is the Wind ?

Si M P The Wind is defined to be nothing clfe but air moved.
OALV. Then the moved air doth carrv Waht
fwiftly, and to a greater diftance, then it Sh ht U ^"^^ """^^
Simp. Yes ccnaidy. ■' ^

S A L V. But if you were to throw with your arm a ftone, and 4

lock ot cotton wool , which would move fwifteft and fartheft ?
^^^SiMP. The ftone by much i nay the wool would fall atinj^

S A L y, , But , if that which moveth the proieaed f..kfl f '
tericisdeliveredfromtheh4nd. beno otL th°m tt ? '
by the arm, and the moved air do more eaf^^r .^ht
than grave matters , how cometh it that the proieft of JniK
not farther, and fwifter than that of ftone? CerLr V
eth that the ftone hath fome other impulfc befides tt ^ ''^"f
the air. Furthermore , if two firings of equ 1 L^^^^^^
atyonderbeam, and at the end of one th^J was faf ^ k"?^
let of ].ad and a ball of cotton wool at ^oLt ^
were earned to an equal diftance from the perpendicular anS^
then let go ; it is not to be doubted , but tha^ both the te anJ
the other wou d move towards the perpendicular , and that bei^g
carried by their own ^mfetus, they would go a c^rta^n fpace S
yondit and afterwards return thither again. But which of theft
two pendent Globes do you think , would continue longeft in mo-
t'on , before that it would come to reft in its perpendicularitv ? I

^i^thlJ^" ^tl t ^""^ T''^ '° '8^'" ™-"y
g tnat ot wool but two or three at the moft.

the caife 1° and that ^i<,iito;, whatfoeveris

fiances thJrnl'. Z \ ^^"^

whidiisapontLt fJL x\bie>° """^ '^'^

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D I A L O G U E i I.

S I M p. Becauie that the air it felf is not moved

S A L V. It is requifite then , that the projicient do confer mo-
tion on the Air , with which it afterward moveth the projeft. But
It luch a motion cannot be impreffed [/. e. imparted'] it being im-
pofliblc to make an accident pafTe out of one hibjeft into another,
how can it pafTe from the arm into the Air ? Will you fay that thu
Air 18 not a fubjeii different from the arm }

Simp. To this it is anfwered that the Air , in regard it is nei=-
ther heavy nor light in its own Region , is iifpofed with facility to
receive every impulfe, and alfo to retain the fame.

S A L V. But if thofe fenduli even now named ^ did prove
^"to us , that the moveable , the leffe it had of gravity , the leffe
^^W k ^^^ ^^ conferve its motion , hovf can it be that the Ait
Which in the Air hath no gravity at all / doth of it felf alone re-^
tarn the motion acquired ? I believe , and know that you by this
tme are ot the fame opinion , that the arm doth not fooner re*^
turn to reft , than doth the circumambient Air. Let's go into the
V^iiamber , and with a towel let us agitate the Air as much as we
^an , and then holding the cloth ftill , let a little candle be
brought , that was lighted in the jlext room , or in the fame blace
let a leaf of beaten Gold be left at liberty to flic any way, and you
fliall by the calm vagation of them be afTured that the Air is imme--
diately reduced to tranquilty. I could alledg many other experi-
ments to the famepurpofe, but if one of thefeftiould notfuf-
"ce , I Ihould think your folly altogether incurable.
^ S A G R. When an arrow is (hot againft the Wind , how in^redi-

k k^^^*^^ ' ^^^^ ^^^^ ^^^^^ filament of air , impelled by
U^ebow-ftring, fliould in defpite of fate go along with the arrow?

^ A would willingly know another particular of AriflotU , to
Wmch I intrcat Simplicius would vouchfafe me an anfwer. Sup*
pofing that with the fame Bow there were fhot two atrows , one
}"ft after the ufual manner , and the other fide-wayes , placing it
long-wayes upon the Bow-ftring , and then letting it flie, I would
know which of them would go fartheft. Favour me, I pray you
with an anfwer, though the queftion may feem to you rather
ridiculous than otherwite and excufe me , for that I, who am, as
you lee , rather blockifli, than not , can reach no higher with my
speculative faculty.

S I M p L. I have never feen an arrow fhot in that manner , yet
^evertheleffc 1 believe , that it would not flie fide-long , the

emicth part of the fpace that it goeth end-way es.
I ha ^ ^* ^ ^^^^ * ^^"^^ opinion, hence it is, that

ve a doubt rifen in me , whether Aristotle doth not contradift

^ . * Qoubt rifen in me , whether JriSiotle doth not contradia
_xperience. For as to experience , if I lay two arrows upon this
^ > in a time when a ftrong Wind blovvcth , one towards

the

134 G. G A LI L i?: u s, his Syjleme.

the coiirie of the wind, and the other fidelong, the wind will
quickly carry away this later, and leave the other where it was j
and the fame to my feeming, ought to happen, if the Doftrine of
ArijiotU were true, of thofc two fliot out of a Bow : forafmuch
as the arrow (hot fideways is driven by a great quantity of Air,
moved by the bowftring, to wit by as much as the faid firing is
long, whereas the other arrow receiveth no greater a quantity of
air, than the fmall circle of the firings thicknefs. And 1 cannot
imagine what may be |he rcafon of fuch a difference, but would
fain know the fame.

Simp. The caufe fecmeth to me fufficicntly manifefl i and it
is, becaufe the arrow ftiot endways, hath, but a little quantity of
air to penetrate, and the other is to make its way through a quan-
tity as great as its whole length.

S A L v. Then it fccms the arrows (hot, arc to penetrate the air ?
bat if the air goeth along with them, yea, is that which carrieth
them, what penetration can they make therein ? Do you not fee
that, in this cafe, the arrow would of neceffity move with greater
velocity than the air ? and this greater velocity, what doth confer
it on the arrow Will you fay the air givcththcm a velocity
greater than its own? Know then, Simpltcim^ that the bufinefs
7** medium w..^ Proceeds quite contrary to that which Anftoth faith, and that the
imp«deMi$dfiotcoK* Medium conferreth the motion on the pro)eft, is as falfe as it is
ferthc mouon of ^^^^^ ^^at it is the onely thing which procureth its obftruftioni and
having known this, you (hall underftand without finding anv thing
whereof to make queftion, that if the air be really moved, it doth
much better carry the dart along with it longways, than endwavs
for that the air which impelleth it in that pofture, is much and it!
this very little. But fhooting with the Bow, forafmuch as the air
Hands ftill, the tranfverfe arrow, being to force its pafTage through
much air, comes to be much impeded, and the other that was nock't
eafily overcometh the obftrudion of the fmall quantity of air.
which oppofcth it felf thereto. 1

Saly. How many Propofitions have I obferved in Arifiotlcy
(meaning ftill m Natural Philolophy) that are not onely falfe,
but falfe in fuch fort, that its diametrical contrary is true as it
happens in this cafe. But purfuing the point in hand, I think that
Simplkius is perfwaded, that, from feeing the flonc always to fall
in the fame place, he cannot conjefture either the motion or fta-
Wity of the Ship : and if what hath been hitherto fpokcn,
fhouldnotfuffice, there is the Experiment of the ntedtnm which
uiay thorowly afTure us thereof in which experiment, the moft
^^.^^^^J^J'^.befeen would be, that the cadent moveable might be
lett behind if it air did not follow the

motion of the (hip : but in cafe the air fhouM move with equal

velocity,

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2°K.B. 9,163

Dialogue IL

Velocity, no imaginable diverfity could be found either in thiSj
or any other experiment vvhatfoever, as I am anon to tell you..
Now if in thi.- cafe there appeareth no difference at all, what can
be pretended to be feen in the ftone falling from the top of the
Tower, where the motion in gyration is not adventitious, and' ac-
cidental, but natural and etenialj and where the air exaftly fol-
loweth the motion of the lower, and the Tower that of the Ter-
rcftrial Globe > have you any thing clfe to fay, SimpliciuSy upon
this particular >

Simp. No aiorc but this, that I fee not the mobility of the
Earth as. y.et proved.

Salv. Nor have I any intention at this time, but onely to
"lew, that nothing can be concluded from the experiments alledg-
ed by Pur adverfaries for convincing Arguments : as I think i
fliall pro.ve .the others to be.

Sag r. I belcech you, Salviatn^^hcioicyovi proceed any far-
ther, to permit me to ftart certain queftions , which have been
rouling inmy fancy i<U the while that you with fo much patience
and equanimity, was minutely jexplaining to Simplieins th^ c^^-^
riment of the Ship. i '

S A L v. We are here met with a purpofe to difpute, and it's fie
that every Que ftiould move the difficulties that he meets withall i
for this is the way to come to the knowledg of the truth.
Therefore fpeak freely. • .a

Sag k. It it be true, that the impettts wherewith the (hip movesj
doth remain indelibly imprelTd in the ftone, after it is let fall from
the Maft j and if it be farther true, that this motion brings no im-
pediment or retardment to the motion direSly downwards, na-
tural to the ftone : it s necelfary, that there do an effefls enfue of
a. very wonderful natuie. Let a Ship be fappofcd to ftand ftill,
^nd let the time of the falling of a fionefrom the Mafts Round-top
^ the ground, be two beats of the pulfe let the Ship afterwards
be Under fail, and let the fame ftone depart from the fame place,
^nd it, according to what hath been premifed, (hall ftill take up
the time of two pulfes in its falU in which time the (hip will have
run, fuppofe, twenty yards •, fo that the true motion of the ftone
will be a tranfverfe line, confiderably longer than the firft ftraight
and perpendicular line, which is the length of the *Maft, and yet
ncverthelefs the * ftone will have paft it in the fame time. Let
itbefartherfuppofed, that the Ships motion is tanch more accele-
^^cd, fo that the ftone in falling (hall be ta pafs a tranfverfe line
"^^ch longer than the other j and in fum, increafing the Ships ve-
^'^^^y as much as you will, the falling ftone (hall defcribe its tranf-

admirable
accid:nt in the mC"
tioHof frojeUs,

*By the length of
the raa'^ he means
the dvflancc be-
tween the iippcr-
d:ck and Round-
top.

* La palla.

vcrfe hnes ftill lojig^j, ^^^d longer, and yet (hall pafs them all in
^nole ielf lame two piJi^s . And in this fa(hion, if a Canon were

level'd

G. G A L I L ^ u s, his Syfieme.

level'd on the top of a Tower, and (hots were made therewith'
point blank, that is, paralel to the Horizon, let the Piece have a
greater or lets charge, To as that the ball may fall fometimes a
thoufand yards diftant, fometimes four thoufand, lomctimes fix,
fomttimes ten, dN<^. and all thefe (hots fliall curry or finifli their
ranges in times equal to each other, and every one equal to the
time which the ball wonld take to pafs from the mouth of the
Piece to the ground, being left, without other impulfe, to fall
fimply downwards in a perpendicular line. Now it fcems a very
admirable thing, that in the fame ihort time of its falhng perpen-
dicularly down to the ground, from the height of, fuppofc an
hundred yards, the fame ball, being thruft violently out of 'the
Piece by the Fire, fhould .be able to pafs one while four hundred.,'^
another while a thoufand, another while four, another while ten
thoufand yards, lo as that the faid ball in all (hots made point
blank, always contmueth an equal time in the air

S A L The confideration for its novelty is v^ry pretty, and i
the eftea be true, very admirable : and of the truth thereof f
make no queftion : and were it not for the accidental impediment
of the air, I verily believe, that, if at the time of the balls going
out of the Piece, another were let fall from (he fame height di-
reftly downwards, they would both come to the ground at th
fame inftant, though that fliould have curried ten thoufan
miles in its range, and this but an hundred oncly : prefuppofin2
thefurface of the Earth to be equal, which to be affuredof the
experimen t may be made upon fome lake. As for the impediment
which might come from the air, it would conllft in retarding the
extreme fwift motion of the fhot. Now, ifyou think fit, we will
proceed to thefolution of the other Objedions, feeing that
plicius (as far as I can fee) is convinc'd of the nullity of this firft'
taken from things falling from on high downwards.

SiMf. 1 find not aJl my fcruples removed, but it may be the
tauJt IS my own, as not bemg of fo eafic and quick an apprehenfion
as S4gred^. And it feems to me, that if this motion, of which
the ftone did partake whdft it was on the Round-top of the Ships
Maft, be, as you lay, to conferve it felf indelibly in the faid ftonc,
even after it is feparated from the Ship, it would follow, that like-
wife in caie any one, riding a horfe that was upon his fpeed, Ihonld
'et a bowl drop out of his hand , that bowl being fallen to the-
ground would continue its motion and follow the horfes fteps
W'thout tarrying behind him : the which effeft, I believe, is not
to befeen, unlefs when he that is upon the horfe fliould throw it

jZ,l^^'''^^'^\^'^^^ but othcrwife,

^ oeiieve u will ftay on the ground m the fame place where it

Dialogue II.

S A L V. I believe that you very much deceive your felf , and am
^Waiujthat experience will Chew you the contrary ,and that the ball
^cing once arrived at the ground, will run together with the horfc,
not ftaying behind him, unlefsfo far as the alperity and uneven-
nefs of the Earth (hall hinder it. And the reafou fcems to mc
very manifeft : for if you, ftanding ftili , throw the faid ball a-
long the ground, do you think it would not continue its motion
even after you had delivered it out of your hand ? and that for fo
much a greater fpace , by how much the fuperficies were more
imooth, io that <v, g, upon ice it would run a great way >

Simp. There is no doubt of it, if I give it impetus with my
^™ : but in the other cafe it is fuppofed^that he who is upon the
horte, onely drops it out of his hand.

Sal V, So I defire that it fllould be : but when you throw it
With your arm, what other remaineth to the ball being once gone
out oi your hand, than the motion received from your arm, which
inotion being confer ved in the boul, it doth continue to carry it
torward ? Now, what doth it import, that that iwp^f;^ be con-
feitcdon the ball rather from the arm than from the horfe? Whilft
you wereoii horfeb^ck, did not your hand, and confequently* the
ball run as faft as the horfe it felf? Doubtlefs it did : therefore
in oncly opening of the hand, the ball departs with the motion al-
ready conceived, not from your arm, by your particular motion,
but from the motion dependant on the faid horfe, which cometh to
be communicated to you, to your arm, to your hand, and laftly to
tbe ball. Nay, I will tell you farther, that if the rider upon his
f peed fling the ball with his arm to the part contrary to the courfe,
It ftall, after it is fallen to the ground, fometimes (albeit thrown to
^e contrary part) follow the courfe of the horfe, and fometin^es lie
on the ground ^ arid (hall onely move contrary to the faid
coUrfe,when the motion received from the arm, (hall exceed that
^* the carrier in velocity. And it is a vanity, that of fome, who
'ay that a horfeman is able to caft a Ravelin thorow the air, that
Way which the horfe runs, and with the horfe to follow and over-

f ^^^^ ' ^^^^^ ^s^^"* * ^^y^ ^ ^^"^^y^

lor that to make the projeft return into the hand, it is requifite to
caft It upwards, in the fame manner as if you ftood ftilL For, let
the carrier be never fo fwift, provided it be uniform, and the pro-
not over-light, it flialUlways fall back again into the hand of
^heprojicient, though never fo high thrown.

. A G R. By this Doftrinc I come to know fome Problems very
™us upon this fubjeftof projeaions-, the firft of which muft
icem very fti-ange to Simplictm. And the Problem is this ^ I af-
jrm It to be pofllble, that the ball being barely dropt or let fall,
y one that any way runneth very fwiftly, being arrived at the

S Earth,

^37

Snndrj cHfhw
Prohftmsy touch*
ing the mothfis of

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2°K.B. 9,163

G. G A L I L ^ u s, hisSyjieme

Earth, doth not oncly follow the courfe of that pei fon, but doth
much out go him. Which Problem is connextd with this, tha
the moveable being thrown by the projicient above the plane <
the Horizon, may acquire new velocity, greater by far than that
confcr'd upon it by the projicient. The which cffcft I have with
admiration obferved, in looking upon thofe who ufe the (port of
tops, which, fo loon as they are fet out of the hand, ar^; i'een to
move in the air with a certain velocity, the which they afterwards
much'encreafe at their coming to the ground ^ and if whipping
them, they rub at any uneven place that makes them skip on high?
they are feen to move very flowly through the air, and falling a-
gain to the Earth? they ftill come to move with a greater velocity ^
But that which is yet more ftrange, I have farther obferved, that^
they not onely turn always more fwiftly on the ground, than in
the air, but of two fpaces both upon the Earth, fometimes a mo*
tioii in the fecond fpace is more fwift than in the firft. Now what
would SimpliciHs fay to this ?

Simp. He would fay in the firft place, that he had never made
fuch an obfervation. Secondly? he would fay, that he did not be
]ieve the fame. He would fay again, in the third place, that if
you could afTure him thereof, and demonftratively convince him (
the fame, he would account yovi a great Daemon*

S A G R. I hope then that it is one of the Socratick, not infernal
ones. But that I may make youunderftand this particular, yoU
muft kriow, that if a perfon apprehend not a truth of himfelf, it
is impoffible that others fhouldmake him underftand it : I may 'in-
deed inftruft you in thofe things which are neither true nor falfe i
but the true, that is, the nei^elTary, namely, fuch as it is impoffible
fhould be otherwife, every common capacity either comprehendedb
them bf himfelfj or elfe it is impoffible he fhould ever know them*
And of this opinjpn I am confident SahiatnszXio : and there-
fore I tell you, that the reafpn? of the prcfent Problems arc knoWA
by you^ but it may be, npt aj>prehended.

S i M P. Let us, for the prefent, pafs by that controvertie> and
permit me to plead ignorance ctf thcfe things you fpeak of, and try
whether you can make me capal>le of underftanding thcfe Fro-
blcms. A

S A G This firft depen(leth upon another, which is. Whence^
Cometh it, that fettinga top with the lafh, it runneth farther, and
confequeptly with greater force, than when its fet with the fill-
gcrs?

S I M p. Ariptk alfo makc$ certain Problems about thefe kinds
of projcSs.

S A i v. He dothfo ^ and very ingebious they are : particular-
ly > That,Whcnc;e itcometh to pafs that round tops run better than
ti^^^%are? Sagi^

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2°K.B. 9,163

I A L 0 G U E

11.

. S A G R. And cannot you, Simplicim, give a reafon for this,
lat Without others prompting you ?

^ ^ ^ Very good, I can fo; but leave your jeering.
' t » '^''c''''' ''"^^^ ^'^^ ^^^fon of this other

i K • 7Jr '"'J^n' ' ''"^^ y^^^ ^'^^^ ^ ^»^i"g which moveth,

of oeing impeded ftands ftill ? ^ ^

P; fuffic^'' * know it doth , if the impediment be fo great as to

ng ^ S A G R. Do you know, that moving upon the Earth is a greater

rh, impediment to the moveable, than moving in the air, the Earth be-

§ ing rough and hard, and the air fofc and yielding ?

^' . , ^ ^"^^^ J luiowing this, I know that the top uill turn faftet

in the air, than on the ground, fo that my knowledgis quite con-
twy to what you think it. ^ ^

^^S^GR. Fair and fofdy, Simplicius. You know that in the
paits ot a moveable, that turneth about its centre, there are found
motions towards all fides i fo that fome afcend, others defcend i
lome go forwards, others backwards ?

Simp. I know it, and Ariftotle taught me the fame.
S A G R. And with what demonftration, 1 pray you-?
Simp. With that of fenfo.

S A G R. Arijloth, then, hath made you foe that which without
him you would not have feen ? Did he ever lend you his eyes>
Youvyould lay, that Anjiotle hath told, advertifed, remembcrea
you ot the lame -, and not taught you it. When then a top, with-
ontx:hanging place, turns round, (or in the childrens phrafe, fleep-
eth) not paralel, but ereft to the Horizon, fome of its parts afcend
and the oppofitc defcend i the fuperiour go one way, the infe-
nour another. Fancic now to your felf, a top, that without chan-
ging p.ace, fwiftly turns round in that manner, and ftands fufpcn-
in the air, and that in that manner turning, it be let fall to the
*j^ith perpendicularly, do you believe, that when it is arrived at
tne ground, it will continue to turn round in the fame manner,
Without changing place, as before ?
• Simp. No, Sir.
Sagr. What will it do then ?
Simp. It will run along the ground very faft.
^ A G R, And towards what part ?
Simp. Towards that, whither its "reeling carrieth it.
do / ^ reeling there are parts, that is the uppermaft,which

which ^^"^^^^y the inferidur •, therefore you muft inftance
the one^ r ^^"^^ ' P^^^^ afcending and defcending,

down 1"^,^'" yi^ld to the others nor will they all go
heavy ' hindered by the Earth, nor upwards as being

' Vcrtigine.

Si M p.

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2°K.B. 9,163

G. G A L I L i^: us, his Syfletne.

Simp. The top will run reeling along the floor towards tha
part whither its upper parts encline it.

S A G R. And why not whither the contrary parts tend, nainely>
thofe which touch the ground ?

S i M p. Becaufe thofe upon the ground happen to be impeded
by the roughncfs of the touch, that is, by the floors unevennefs j
but the fuperiour, which are in the tenuous and flexible air, ar"
hindred very little, if at all j and therefore the top will obey th
inclination.

S A G R. So that that tadion, if I may fo fay^ of the ncith
parts on the floor, is the caufe that they ftay, and onely the up
parts fpring the top forward.

Sa L V. And therefore, if the top fliould fall upon the ice,
other very fmooth fuperficies, it would not fo well run forward bu
might peradvcnture continue to revolve in it felf, (or flecp) vvith-
out acquiring any progreflivc motion.

S A G R. It is an eafie thing for it fo to do j but yet neverth
lefs, it would not fo fpeedily come to fleep, as when it falleth o
a fuperricies fomcwhat rugged. But tell me, SimpUcins^ when
the top turiiing round about it fclf, in that manner, is let fall, why
doth it not move forwards in the air, as it doth afterwards when it
is upon the ground ?

Simp. Becaufe having air above it, and beneath, neither thpfc
parts, nor thefe have any where to touch, and not having more oc^
cafion to go forward than backward, it falls perpendicularly.

Sagr. So then the onely reeling about its felf, without'other
impetHs, can drive the top forward, being arrived at the ground,
very nimbly. Now proceed we to what remains. That lafli>
which the driver tyeth to his Top-ftick, and with which, winding
It about the top, he fcts it (i. e. makes it go) what effed hath it on
the faid top ?

Simp. It conflrains it to turn round upon its toe, that fo it may
free it felf from the Top-lafli.

S A G R. So then, when the top arriveth at the ground, it comctb
all the way turning about its felf, by means of the lafli. Hath it
not reafon then to move in it felf more fwiftly upon the ground?
than it did whilft it was in the air ?

Simp. Yes doubtlefs j for in the air it had no other impulfc
than that of the arm of the projicicnt i and if it had alfo the reel-
ing, this (as hath been faid; in the air drives it not forward at all ;
D^t arriving at the floor, to the motion of the arm is added the
progrefllon of the reeling, whereby the velocity is redoubled. And
I know already very well, that the top skipping from the ground?
Its velocity wiU deminifli, becaufe the help of its circulation ts
wanting j and returning to the Earth will get it again, and by that

meanJ^

Dialogue. 11.
nieans move again fafter , than in the air. It onely refts for me to
underftand 3 whether in this fecond motion on the Earth it move
more fv^^iftly , .than in the firft , for then it would move in injini-
fJtffi 5 alwayes accelerating.

S A G R. 1 did not ablolutely affirm ^ that this fecond motion is
more iwift than the firft . but that it may happen fo to be fome-
limes.

Simp. This is that, which I apprehend not, and which I
dcfire to know.

Sagr. And this alfo you know of your felf. Therefore tell
tue : When you let the top fall out of your hand , without ma-
king it turn round (/. e. fetting it) what will it do at its coming to
the ground ?

Simp. Nothing , but there lie ftill.

Sagr. May it not chance , that in its fall to the ground it may
acquire a motion ? Think better on it.

Simp. Unleffe we let it fall upon fome inclining ftone , as
children do playing at* Cfei(?/<f , and that falling fide-wayes upon
the fame , it do acquire the motion of turning round upon its toe,
wherewith it afterwards continue th to move . progrefiively oft the
floor , I know not in what other manner it can do any thing but
lie ftill where it falleth.

Sagr. You fee then that in fome cafe it may acquire a hew
revolution. When then the top jerked up from the groundy jfalleth
down again , why may it not cafually hit upon the declivity of
fome ftone fixed in the floor , and that hath an inclination that
Way towards which it moveth , and acquiring by that flip a new
wtirlc over and above that conferred by the lafti r why may it
not redouble its motion , and make it fwifter than it v\^<is atits
firft lighting upon , the ground ?

Simp. Now I fee that the fame may eafily happen. And I
^ni thinking that if the top ftiould turn the contrary way , in ar-
riving at the ground , it would work a contrary effefi: 5 that is,
the motion of the accidental whirl would retard that of the pro-
ficient.

Sagr. And it would fometimes wholly retard and ftop it 5 in
cafe the revolution of the top were very fwift. And from hence a-
rifeth the refolution of that flight , which the more skilful Tennis
Players ufe to their advantage i that is, to gull their adverfary by
cutting (forfo is their Phrafe) the BalU which is, to return it
^ith a fide Rachet , in fuch a manner , thaC it doth thereby ac-
quire a motion by it felf contrary to the projefted motion , and fo
by that means , at its coming to the ground , the rebound, which
It the ball did not turn in that manner , would be towards the
^verfary , giving him the ufual time to tofleit back again , doth

failj

141

* A Game in /m//,
which is, to glide
btll rs down an
inclining* ftone ,
dr.

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2°K.B. 9,163

14 i

G. G

ftil , and the ball

A L I L iEUS

his Syfl^

erne.

runs tripping along the ground, or rebounds leffe

return. Hence it is

than ufual , and breaketh the time of the

AGamem//*/;, that you fee , thofe who plav at • Sronl-K^ll Jul .u^'^^^^t

who (hall CMindle

afTigncd mark.

~ u^r^T ;-F^-f"" of holes aid rubs Z^X^ffi
thrcw.woodcn trip an hundred fcvcral wayes , never fufFering it to come neer the

ground , but throw ,t , as ,f they were^to pitch a qu.it. But be-

rolhtc" H ¥ '^u^f' " 'ff-thout'^-the hand withlW
rohng conferred by the fingers whenever the hand is underthc
ball as ,t IS moft commonly held^ whereupon the ball in its li^ht "g
on the ground neer to the mark , between the rnnr inn f P ^
Jicient and that of the roling /woulTmn a "
fame : To make the ball ftay^ thThoM h ' ^'^^'.^^y ^Tu^!

^clr/Twti 'or ' Vi ^'^^"-^^^ s

wh'erTof i" tsTmirtftL^tS ^Iri^^^i^^
there, or runs very very little forwards Rnr? ^
princip^ problem which gave occafion for ftartmfe^^^^^^^^
fay K ,s poffible that a perfon carried very fwiftly^ mayTe ^ baJ
dropout of Ins hand, that being come' to the Earth' fta 1 r^t
onely follow his mot.on, but alfo out-go it , moving with a are«-

mav beS f T?^^' ' ^^^^ tittheclS

may be that of a Chariot to which on the out-fide let a decli-
ning board be fattened ; fo as that the neither part may b" towaS
the horfcs , and the upper towards the hind Wheel N f -

theChariotsfullcareer, amanwithmit, letaSlfafc ' "
long the declivity of that board, it ftall in roirnj j^''*^'^ ^'
quire a particular .ern.o or tur'ning , 2T'^ X

motion impreffed by the Chariot , I II c irie th A fnf f
ground much fafter than the Chariot. And if on
another declining board over againfi it accommodate
riot may be qualified fo , that theball ' ,J ""^"o" ^ ^ Gha-
the board, in its coming to he i^^^^^^
and alfo (hdl fometimes ru^n the con^t" y tfll if ^T^'^f '

B-^StL^^^^^^^

"»'rer ^^^^^ t

fromth'' The digreflions made hitherto, are not fo alienated

^ at fia ; ? f argumentations depend on thofe

thatle a'e " "P;"^''^^^"^y not of one perfon , but of three,
arewe-obWd " r'^^'"^ V ^"^Pl-afure, nor

methodically of ft^-aneffe of one who e. frofeffo tre'ateth

yot an argument, with an intent to pubJift.thc fame

D ! A LOG a E. I L

1 will not confciit that our Poem flioiiIJ be lb confined to that
unity , as not to leave us fields open for Epfody*s , which every
Imalll connection fhould lufficc to introduce , but with almoft as
much liberry as if we were met to tell ftories , it fliall be lawful
for me to Ipeak , what ever your difcourfe brings into mymind.

S A G R. I like this motion very well j and fince we are at this
liberty , let mc take leave ^ before we paffe any farther to ask of
yon SahiatHS ^ whether you did ever confider what that line may
be that is defcribed by the grave moveable naturally falling down
from the top of a Tower - and if you have reflefted onit^ be
pleafed to tell me what you think thereof

S A L V. 1 have fometimes confidered of it ^ and make no que-
stion 5 that if one could be certain of the nature of that motion
wherewith the grave body defcendeth to approach the centre of
the Terreftrial Globe , mixing it felf afterwards with the common
circular motion of the diurnal converfion , it might be exaftly
tound what kind of Hnc that is , that the centre of gravity of the
moveable dcfcribeth in thofe two motions.

S A G R. Touching the fimple motion towards the centre de-
pendent on the gravity , I think that one may confidently , with-
out error , believe that it is by a right line , as it would be , were
the Earth immoveable.

S A L V. As to this particular , we may not onely believe it, but
experience rendereth us certain of the fame.

S A G R. But how doth experience affure us thereof, if we ne*
ver fee any motions but fuch as are compofed of the two , circular
and defcending.

S A L V. Nay rather Sagrcdus we onely fee the fimple motion of
^Iccnt i fince that other circular one common to the Earth , the
Tower aiid our felves remains imperceptible , and as if it never
jvcre, and there remaineth perceptible to us that of the ft one , one-
fy not participated by us , and for this, fenfe demonftrateth that
't is by a right line , ever parallel to the faid Tower , which is
built upright and perpendicular upon the Terreftrial furface.

Sag r. You are in the right i and this was but too plainly de-
monftrated to me even now , feeing that I could not remember fo
^afic a thing ^ but this being fo manifeft , what more is it that you
*^ay you defire , for undcrftanding the nature of this motion
downwards >

A L V. It fufficeth not to know that it is flreigbt , but its requi-
ite to know whether it be uniform , or irregular , that is , whe-

" Maintain alwayes one and the fame velocity , orelfeeocth
retardmg or accelerating,

tati ^ ^ ^ " already clear , that it goeth continually accelle-

S A L V,

r45

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2°K.B. 9,163

• This is that ex-
cellent irafl which
we give the fi
place in our fecond
Volum?.

G. G A L I L ^ u s , his Syfieme.

S A L V. Neither doth this fiiftice , but its requifite to know ac-
cording to what proportion fuch accelleration is made , a Pro-
blem , that 1 believe was never hitherto underftood by any Phi-
loiopher or Mathematician ; although Philofophcrs, and particu-
larly the ¥ eripatetickj , have writ great and entire Volumes,
touching motion.

Sjmp. Philofophers principally bufie themfelves about univer-
fals, they find the definitions and more common fymptomes , o-
mitting certain fubtilties and niceties , which are rather curio^
fities to the Mathematicians. And Ari^iotle did content himfirlf
to define excellently what motion was in general j and of the lo-
cal, to (hew thjpriiKipal qualities, to wit , that one is natural,
another violent *, one is fimple , another compound r one is
equal, another acccller ate j and concerning the accelerate , con-
tents himfclf to give tli- reafon of acceleration , remitting the
finding out of the proportion of fuch acceleration , and other
particular acciderlts to the Mechanitian , or other inferiour
Artift.

S A G R. Very well Stmpltctus. But you Sahiatus , when you
defccnd fometimes from the Throne of Peripatetick^ Majefty,
have you ever thrown away any of your hours in ftudying to find
this proportion of the acceleration of the motion of defcending
grave bodies ?

S A L V. There was no need that I fliould ftudy for it , in regard
that the Academick our common friend , heretofore (hewed me a
Treatife of his * De Motn , where this , and many other acci-
:h dents were demonftrated. But it would be too great a digreffion,
if for this particular / we fliould interrupt our prefent difcourfc,
(which yet it felf is alfo no better than a digreflion) and make a^'
the Saying is , a Comedy within a Comedy.

S A G R. I am content to excufc you from this narration for the
prefent, provided that this may be one of the Proportions refer-
ved to be examined amongft the reft in another particular meeting,
for that the knowledg thereof is by me very much defireiJj and
in the mean time let us return to the line defcribed by the grave
body in its fall from the top of the Tower to its b'afe.

S A L V. If the right motion towards the centre of the Earth was
unlforme , the circular towards the Eaft being alfo uniforme, you
would fee compofed of them both a motion by a fpiral line , of^
that kind with thofe defined by Archimedes in his Book Dc Spira'
noHs which are , when a point moveth uniformly upon a right
Ime, whileft that line in the iftean time turneth uniformly about
one or its extreme points fixed , as the centre of his gyratioH'
But becaufe the right motion of grave bodies falling , is continu-
ally accelerated, it is neceffary, that the line refulting of the

com-

D I A L O G ll E l \.

Compofltion of the two motions do go alwayes receding With
greater and greater proportion from the circumference of that cir~
cle , which the centre of the ftones gravity would have defigned,
if it had alwayes ftaid upon the Tower j it followeth of neceflitjr
that this rcceflion at the tirft be but little , yea very fmall , yea,
more, as fmall as can be imagined , feeing' that the defcending
grave body departing from reft , that is j from the privation of
motion , towards the bottom and entring into the right motion
downwards , it muft needs pafle through all the degrees ot tardi-
ty , that arc betwixt reft , and any afligned velocity *, the which
degrees are infinite j as already hath been at large difcourfed and
proved.

It being fuppofed therefore , that the progrefle of the accele-
ration being after this manner , and it being moreover true , that
the defcending grave body goeth to terminate in the centre of the
Earth , it is neceflary that the line of its mixt motion be fuch, tha t
J5 go continually receding with greater and greater proportion
Atom the top of the Tower , or to fpeak more properly , from
tlie circumference of the circle dcfcribcd by the top of the Tower,
by means of the Earths convcrlion j but that fuch receffions be
leflir and Icffer in injinitHm j by how much the moveable finds it
fclf to be lefle and lefle removed from the firft term where it
refted. Moreover it is neceflary , that this line of the compound-
ed motion do go to terminate in the centre of the Earth. Now
having prefuppofed thefe two things , I come to dcfcribe about
the centre A linFig. i. of this fee ond DialogHe',^ with thefenti;
diameter A B 5 the circle B I , reprefenting to me the Terreftrial
Globe , and prolonging the femidiamcter A B to G , I have dc-
fcribcd the height of the Tower B C j the which being carried
^oout by the Earth along the circumference B I , defcribeith with
Its top the arch C D : Dividing, in the next place, the line G A
in the middle at E ; upon the centre E, at the diftancc E G , I dc-
fcribe the femicircle CIA: In which, I now affirm , that it is vcty
probable that a ftone falling from the top of the Tower C , doth
move, with a morion mixt of the circular, which is in common,
and of its peculiar right motion. If therefore in the circumference
C p certain equal parts C F, F G, G H, H L , be marked , and
from the points F, G, H, right lines be drawn towards the
^^nrre A , the parts of them intercepted between the two cir-
^l^^erences C D and B I , fliall rcprefent unto us the fame
i owcr C B , tranfported by the Terreftrial Globe towards D I j
in which lines the points where they come to be interfered by the
arch of thcfemicircle G I , arc the places by whichfrom time to
w"^K f^lling.ftone doth paflb which points go continually

ith greater and greater proportion receding from the top of the

T Tower.

i4t

• Thlintiefcri^
hed bj a moveahlk
in its matursi 4i*
[cent ) the rmtion
of the Enrth 4-
voMt its own centre
being frefuppofed,
rpou/d prohaBlj be
the circumference
of A ctrclei

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2°K.B. 9,163

14^

liiigfrom the top of
the'Tomr, moveth
in the ' circffmfc
tyhce bf '4 ctrcle,

ft moveth neither
more r.or lejfe, iban
ffit' had JfaU ai^
•wajes there.

It moveth tvith
an Uniform , not
aecilerate mor
tion.

Tow€i. And this is the caufc why the tight mo tip n made aiong
the fide of the Tower appeareth to us more and more accelerate*
It appeareth alfo , how by reafon of the infinite acutenefli of
ttie contaa of thofe two circles D C, C I 5 the rcceflion of the
cadent moveable from the circumference C F D j namely, fioflJ
^'^^L ^op Tower , is towards the beginning cxtream linall,

which is as nmch as if otie faid its motion downwards is very flow,
and more and more flow ifi infimtHm , according to its vicinity to
the , term C , that is to the ftate of reft. And laftly it is feen ho\V
in the end this fame motion goeth to terminate in the centre of the
Earth A.

S A G R. I undcrftand all this very well , nor can I perfwade mj
felf that the falling moveable doth defcribe with the centre .of^ its
gravity any other line, but fuch an ope as this. . , • «

/^S A L v- Butjftay a little Sagredns , for 1 am to acquaint >yoU
alfp vyith three Obfervations of mine ^ that its pofllble will nocdif*
picafe jou. The firft of which is, that if we do well confider, the
mpv^eable momh not really with any more than onely one motion
fimply,circular, as when being placed upon the Tower, it moved
with ojic finglp and circular motion. The fecond is yet moreplea^
fanjt;;i.|or, i£ mp;Yeth neither more nor lefle then if it had ftaid cc«i-
Si^^ily "PPn thp Tower,, being that to the arches G f , F C^G .H
8<;G,.thaf:it; waAMhavc pafl<p4 continuing alwayes upon th^ TbwtT)
th^.^Tchgeof'the circumference C I are exaftly <rqual , snitwen^
my^f^ the faipfc CiF, F Q,iG H, &:c. Whence folWeth the thifd
w9n4ex>,T*iat'tJie true sind i^al motion of nhc ftone is never acce-
kr^^Ai tet_4w;^yes even ai)d uniforme, fince that all the equal af"
cl«sj^9fp^ in circumference C D,"<^nd their refpondent oiie^
ma^ke4 iA.tlw. ^irqumfet-^nceC I.^ /^dcjpaft in equal times^ fo'tba*
Wfi7^rftkf5ali }ii)erryit9je^^^^^ of aiccekration , or ofc*

t|h«>iWMioa% fe^iftg tha(5 tjfc i3PK)veatile*f6| weH^ft^nding upoja tto
T,%vTcv',.as d^ftciiv^iag th^ncej alw'ayesilinovethinfthc famc fafliioiJ^
^%K'ifi§?^*^#^ ^ith.<:h^.fe and wichithe fahaeLUi*

fmit^ S^p.^feireHmQ Wi^J yOu/ thiikk^of this my fantafticai.con*^

- .§^:ffftv liWrfi i^htt li^ahnot witii iKbrds^iffiaerftlf I

expreflp hp%^^\r44e itifeemoth m e)e j and ;fpc what at^ ptc^
fent pf3;ereth i^ fcjf^^ro thy nrideijft,an4ii|g,' I cannot think thatiuW
hi|fiajffi; hagp^neth otlijerwifej and.vvduld to God that'aUj^ '
d^^nftratiqn^ of Phil<rfpphers wiere.blit half fo probable as this-'
^?>i!He7C:r for my perfcft fa^isfiiilion i wduld gl«diy iheat; how yoi i
Pfpvfdkpfe arches to be e^l. / • - r , aoiJ .v o'j - : r ,i,iv/^^*
. S k^v Tbdj^^mojniiratioti ismoft eafc^ Suppofe to ycm^X^^
a,1^.4rawn from-Jit<^Ei' A'n^I the Seinidiametec of the circle CB>V
tWifa)t#€ lii^!^<j,^^ b€ibg,d9wbk the Semidiametcr C E ai H

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2°K.B. 9,163

I A L O G U E

£01

the

Circle C I, the chcumference fliall be double to the circumjference.

and

like arch of

*Vadia <lcl cucco a
monte, rendered im
the Latine o rani-
no pcflum cat.

every arch of the greater circle double to every
the leffer ^ and coalequently, the half of the arch of the greater
circle, equal to the whole arch of the leffc. And bccaufe the an^-
gle C E I made in the centre E of the leffer circle, and which infi-
fteth upon the arch C I , is double the angle CAD, made in the
centre A of the greater circle, to which the arch C D fubtendeth,
therefore the arch C D is half of the arch of the greater circle like
to the arch C 1, and therefore the two arches C D and C I are e*
qual j and in the fame manner we may demonftrate of all their
parts. But that the bufinefs, as fo the motion of defc^nding grave
bodies, procecdcth cxaftly thus, 1 will not at this time affirm but
this I will fay, that if the line defcribed by the cadent moveable
be not exaSly the fame with this, it doth extream neerly refcmblc
the fame.-

S A G R. But LSalviatHS^ am juft now confidering another par-
ticular very admirable ; and this it is ^ That admitting thefe con- ^^^fj^I^^T'
^derations, the right motion doth go wholly * mounting, and that ^ *^ ' '"•^f*'''-
Nature never makes ufe thereof, fince that, even that that ufe,
which was from the beginning granted to it , which was of redu-
cing the parts of integral bodies to their place, when they were
feparated from their whole, and therefore conftituted in a depra-
ved difpofition , is taken from it , and affigned to the circular
motion.

S A L V. This w ould neceffarily follow , if it were concluded
that the Terrcftrial Globe moveth circularly *, a thing, which I
pretend not to be done , but have onely hitherto attempted , as I
fliall ftill , to examine the ftrength of thofe reafons , which have
been alledged by Philofophers to prove the immobility of the
Earth , of which this firft taken from things falling perpendicu-
larly , hath begat the doubts , that have been mentioned . which
1 know not of what force they may have feemed to Simplicius',
and therefore before 1 paffe to the examination of the remaining
arguments , it would be convenient that he produce what he hath
to reply to the contrary.

Simp. As to this firft , 1 confeffe indeed that I have heard
fundry pretty notions , which I never thought upon before , and
in regard they are new unto me , i cannot have anfwers fo ready
for them, but this argument taken from things falling perpendi-
cularly, leftecmit not one of the ftrongeft V^^^^ mobi-
o!^ ^^^^^ ' ^ '^"^^ ^^^^ happen touching the

mots of great Guns, efpccially thofe aimed contrary to thediur-
nal motion.

S A G R. The flying of the birds as much pfizzleth me as the
^Djcfiion of the Gun-fliot , and all the other experiments above

T d ak

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2°K.B. 9,163

148

ThirCMfoH why
a Gun (hould feem
to carrj farther' to-
wards the tycfl

than ttfvards the

The cxyeriment
of a rttani^^ chd"
riot to find cut the
difference of Ran-

•Baleftronc da bol-

G. G A L I L u s, his Sylleme,

alledged. For thefe birds which at their pleafure flic for-
wards and backwards , and wind to and again in a thoiifaiid
fafiiions, and, which more importeth , lie whole hours upon the
wing 9 thcfe I fay do not a little pofe me., nor do I fee , how a-
mongft fo many circumgyrations , they fliould not lofe the motion
of the Earth , and how they (hould be able to keep pace witfc
fo great a velocity as that which they fo far exceed with theif
flight. , _ >

Sa l*V'.> To fpeak the truth, your fcruple is not without reafon,
and itspoflible Copernicm himfelf could not find an anfwer for if/
that was to himfelf entirely fatibfaftory , and therefore haply paft
it over in filence j albeit he was, indeed, very brief in examining
the other allegations of his adverfaries , 1 believe through bis
height of wit, placed on greater aud fublimer contemplations,
like as Lions are not much moved at the barking of little Dogs.
We will therefore referve the inftance of birds to the laft place,
and for the prefenc^^ fee if we can give Simphcius fatisfafiionin
the others , by fliewing him in our wonted manner, that he him-
felf hath their anfwers at hand , though upon firfi thoughts b^
doth not difcover them. And to begin with the fhots made at ran-
dome>withthefelf fame piece, powder, and ball, the one towards
Eaftjthe other towards the Weft (if the diurnal converfion belong-
ed to the Earth) ought to be much longer than that towards Eaft.

S vM p. I am moved fo to thinks becaufe in the (hot made to-
wards the Eaft , the ball whiFft it is out of the piece , is follow-
ed by the faid piece , the which being carried round by chc Earth,
runneth alfo with much velocity towards the fame part , whcr^*
upon the fall of the ball to. the ground , cometh to be but littk
diftantfrom the piece. On the contrary in the (hot towards the
Weft , before that the ball falleth to the ground , .the piece is
tired very far towards the Eaft , by which means the fpace be-
tween the ball and the piece, that is Range, will appear long'
than the other , by how much the piece , that is the Earth , ha
run in the time that both the bals were in the air.

S A L V. I could wi(h 3 that we did know fome way to make ai¥
experiment corrcfponding to the motion of thel'e projcfts , as that
of the (hip doth to the motion of things perpendicularly falling
from on high j and I am thinking how it may be done.

Sagr. 1 believe, that it would be a very oppofite proof , to
take an open Chariot , and to accomodate therein a * Stock-bow

half elevation , to the end the flight may prove the greateft
that tny be , and whil'ft the horfes (hall run, to (hoot firft towanl^
the part whither you drive 5 ^^^^^ another backwards towards
the contrary p^rt ^ cau(ing fome one to. mark diligently where
the Chariot was in that moment f time when the (hafc came to

th<?

ialoghe.

11.

ill

le ground, as well in tlie one (hot as in the other : for thus you

iec cKaftly how

fliaftf

' farther than the

... J) I M ?* in my tnpugnts tnis experiment is very proper : and I
do noc doubt but that the flight, that is, the fpace b^tvVecn the
ftaft and the place where the chariot was at the fliafts fall, will be
Icfs by much when one fliooteth towards the chariots courfe, than
when Qnciihooteth then^ontrary way. For an exani^le, let the
flight of it felf be thriec hundred yards, and th6 cdurfe of theeha-
riQc in, tj)^ time whilft the fliaft ftayeth in the air, an hundred
yards, Jife^^^f pre fliootirig towards the courfei of the thrfee htindred
ift yards of the flight, the chariot will have gdhe one hundred j fo

then at the fliafcs coming to the ground, the fpace between it and
the charidtf ihall be but two hun&e^ yards oliely but 6n the
contrary, in the other flioot, the chariot rurinihg contrary to th^
ftiaft, when the (haft (hall have palTed its three hundred yards, and
the chari<)t its other hundred -the contrary way, the diftanCe inter-
poling (hall be found to be four hundred yards.
: Sal V,. Is there aayiwayto ihoot fo that thefc flights may be
«4Uitl h ol ; r , :uh '

S I M p. I fciow no Other way, unlefs by making the chariot to

Sal V,. This we know j but I mcafl when the chariot rtinneth
full carreer. - - .

Simp. In that cafe j/bu are to drav^ the Bow higher m fliodt^
ing forwards, and to flack it in ftaoting the contrary way.
jb, S A L V. Then you fee that there is one way mote. Biit fe^

much is the bow to be drawn, and how much flackened ? ■ '■
tic S i M Pi In our cafcj where we have fuppofed that the bbw ^:ar-

ried three hundred yards, it would be rcquifite to draw it fo, as
that it might carry four hundred, and m the other to flacken it fo,
that it might carry no more than two hundred. For fo each
^f the flights would be but three hundred in relation to the chariot,
the which, with its courfe of an hundred yards which it fubftrafts
from the flioot of four hundred, and addeth to that of two hun-
dred, would reduce them both to three hundred.

S A L V. But what effeft hath thd greater or lefs mtenfi^efs of the^
bow upon the fliaft?

Simp. The ftift'er bow cirrieth it with greater velocity, and the
weaker with lefs and the fame fliaft flieth fo fnuch farther at one
tune than another, with how much greater velocity it goeth out of
y^^ler at one time, than another.

iV ^^^^ ^^^^ ^^^^ ^^^^^^ ^"
^"^^^^ft^nce from the running chariot, it is r&quifite, that if in the

tirlt Ihoot of the precedent example, it goeth out of the tiller with
"^•g. four degrees of velocity, that then in the other flioot it de-
part

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2°K.B. 9,163

The folmion tf
thi ari^umertt ta-
ken from gredt-
Ghus fhot towards

the E^n & mjt.

G. G A L I L if: u s ^ his SjifJeme.

part but with tvvoonely : but if the fame bow be ufed, it always
receive th thence three degrees.

Simp. It doth foj and for this reafon, (hooting with the
fame bow in the chariots courfe, the (hoots cannot be equal.

S A L V. I had forgot to ask, with what velocity it is fuppofed in
this particular experiment, that the chariot runneth.

Simp. The velocity of the chariot muft be fuppofed to be one
degree in comparifon to that of the bow, which is three,

S A L V. Very right, for io computation gives it. But tell me,
when the chariot moveth, doth not all things in the fame move
with the fame velocity >

Simp. Yes doubtlefs.

S A L V. Then fo doth the (haft alfo, and the bow, and the firing,
upon which the (haft is nock*t.
S I MP. They dofo.

Salt. Why then, in dilcharging the fliafc towards the courfe
of the chariot, the bow impreffeth its three degrees of velocity on .
a (haft that had one degree of velocity before, by means of the
chariot which tranfported it fofaft towards that part ^ fo that in
its going ofFit hath four degrees of velocity. On the contrary,
in the other (hoot, the fame bow conferreth its fame three degrees
of velocity on a ihaft that moveth the contrary way, with one de-
gree ; fo that in its departing from the bow-ftring, it hath no more-
left but pncly two degrees of velocity. But you your felf have
already laid, that the way to make the (hoots equal, is to caule
that.the.fliaft be let flie the firft time with four degrees of velocity,
and the fccond time with two. Therefore without changing the
bow, the very courfe of the chariot is that which adjufteth the
flights, and the experiment doth fo reprefeht them to any one who
IS not either wilfully or naturally incapable of reafon. Now
apply this difcourie to Gunnery ,and you (hall find^that whetherthc
Earth move or ftandftii], the (hots made with the fame force, will
always curry equal ranges, to what part foevcr aimed. The error
olAriftotle, Ftolomey, iycbo, your felf, and all the reft, is ground--
cd upon that fixed and ftrong perfuafion, that the Earth ftandeth
ftill, which you have not judgment nor power to dcpofe, no not
when you have a defire to argue of that which would enfue, pre-
fuppofing the Earth to move. And thus, in the other argument,
Jiot con(idering that whifft the ftone is upon the Tower, it doth
^sto moving or not moving, the fame that the Terreftrial Globe
doth, becaufe you have concluded with your felf, that the Earth
ftands ftiu^ always difcourfe touching the fall of the ftone as
if It were to depart from reft : whereas it behooveth to fay, that
it the Earth ftandeth ftill, the ftone departeth from reft, and de-
fcendeth perpendicularly^ but if the Earth do move, the ftone

likewifc

Dialogue. IL

likewii'c movcth with like velocity, nor doth it depart from reft,
but from a motion equal to that ci the Earth, wherewith it intcr-
mixeth the lupervcnient motion of defcent, and of thofe two com-
pofeth a third which is tranfverfal or fide-ways.
...Simp. But for Gods, fake, if it move tranfverfly^ hdvvis it that
I behold it to move direftly and perpendicularly ? This is no bet-
ter than the denial of manifeft fenfe, and if we may tiot believe
fcpfe, at what otlier door fliall we enter into difqaifitlibns of Philq-
lophy ? ' '

w) A L V. In refpeS to the Earth, to the Tower, and t&oiii felves,
wJiiqh all as one piece move with the diurnal motifon together with
the ftone, the diurnal motion is as if it never had been, and becom-
^th infenfible, imperceptible, and without any aftion at ill j and
the onely motion which weican perceive, is that of which ii^e par-
take not, thatis the deicent gliding along the fide of the Tower :
\jQU afenptjthe firft that hath feltigrcat repugnance ili apj^rehen-
9»fig this Bon-qperating QfirhAtiowApon things' tb whitH ifc^ls com-

o'SfpR-. I^pw;,J:.dQ remember a certain coiftcif^t, that •'ckflit' brie
d^y^i^Q^y ftncy, whUft I failed sin my voyage to yf/^^/?(7,* Whither
I. wenjt Coofulr for our Comitrey, and pofltbly it may fee df fome
.uf9^ jfoc,explaiaingthis nullity of operation 'cf <^6rrtmoh tn^ition,
W4.)!^^ii^g^s if it never were to all the partakers therte^.'^^^AWif
with th^ good liking oi SifH^littHsi I will reafdn with
hiuft,upon tha^tj^wbich then I thought of by itly felf alone-
A 5 \^ ^ ^ ; T^e povielty of the thiogs iwhich 1 hear, rtiakc^ me not
"^>W.W?^ia,i^%^iefil:i as a greedy and curious audit6t= : ^thefyft^re go

I? I

tyf notablt Cdfe
o/Sagrcdus, to [hew
the non-operstitj^
of common motion^

IjVuI ill ji'i;.

: j|^]6,PR>, If ^/i>eb of a, writing pclii^ > that f ;drfffed aJqfej^' '^/^^
fl?ff)i9,t^e fhipjiit^ough aJJ my navigation frortv' P^^yrce i& '^'Scaii- * AlefTandretu.
^^f>ff^ \i^4 h^d a^ facUltic of leaving vifible' m^tks of hi whole v6y-
?8^!^Hhatfig)is; what marks, what lines would it have left ?
ilj^ ji^W ^ ,lR !*K>wld.ha\^dleft a line diftended from Fewire thither,
iPqrf^aiy ftfieig/it, orttoifay better, diftend^d in a perfeft arch
of a circle, but in fome places nK>re, in fome left burvedj according
.¥/;h?iM^elhad;goiie moreor lefs,Buatiating { But this it ^ infle-
^^gcinf'pme places a feithom or two to the right' hatid Of tb the
4^5 ^pward^.pr4ownwa^ds,ina length- of m^4rty hdndr^id; miles^,
have brought hut little alteration tb th^ >2iJtrrd traft of the
^^ne, fo that it would have been hardly fenfible ; aiid without any
^^¥l^ablc|pyi.oj;^^,rtight have been edlcd tW^rk-bf ^erfeft

-•Jof ^R^;/ 3f>^5:ba; the trou and moft^exagl motion of the rieb of
^y^^m4iMy€f\[f^h'tvvi^^ of a pcrfea circle, if the
JSH^l? /F^.^ii(/he fluaiiation. of ' the billows ceafing, had been
i'iWit calm

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2°K.B. 9,163

G. G A L I L « u s , his Syfleme.
calm and traaquill. And if I had continually held that ben in
my hand, and had onely moved it fometimes an inch or tsxo this
way or that way, what alteration lliould I have made in that its
principal, and very Jong trafi or ftroke >

S , M P. Lefs than that which the declining in federal places from
abfolute reaitude, but the quantity of a flea's eye makes in a right
line of a thoufand yards long. ^

S A G R. If a Fainter, then, at our launching from the Port, had
began to defign upon a paper with that pen, and continued bis
work till he came to Scanderon, he would have been able to have
taken by its motion a perfed draugEt of all thofe figures perfealV
mterwoven and lhadowed on feveral fides with countreys, build-
ings, living creatures, and other things j albeit all the true, real,
and effential motion traced out by the neb of that pen, would
have been no other than a very long, butfimple line : and as to
the proper operation of the Painter, he would have delineated the
fame to an hair, if the ftip had ftood ftill. That the efore of the
huge long motion of the pen there doth remain no other mark
than tJiole tracks drawn upon the paper, the rcafon thereof i, bc-
caule the grand motion from Venice to Scanderon, was common t
the paper,the pen, and all that which was in the ftip : but the pet
motions forwards and backwards, to the right, to the left coir-
.municated by the fingers of the Painter unto the pen, and 'not to
the paper, as bcng peculiar thereunto, might leave marks of it felf
upon the paper, which did not move with that motion. Thus it
,s Itole true, tha^t fhe Earth moving, the motion of the fton" jfl
defcemlmg downwards, w.s really a long trad of many hunted"
and thoulands of yards, and if it could have been able to have de-
lineated m a calm ar, or other fuperficies the tr^.\, c- r
it would have l,ft behind an h^e^fng^^^l^tSln:' ^ i
part of all this motion which is common to the ftone, the Tower,
and our fcJves, is imperceptible to us, and as if it had never been,
and that part On^ly remaineth obfervable, of which neither th

Tower ^or we ;,r, partakers whichis in fine, that wherewith tK
Itone falling incafureth the Tower.

not a httl^ difficult to many capacities. Now if Simphcim will
make no farther reply we may pafs to the other experiments, fhc
untolding of which will receive no fmall facility from the things
Already declared. i - (. I

ported w- ^uT Ti*"'"^ \ '"^ ' well-nigh tranf-

drawn fot delineation, and with thinking how thofe ftrokes
vl2 h^Tv^'^ r^\^''^^'' thither, upwards, downwards, for-
w^rag Dackvvards, and interwoven with thoufands of turninps are
not eflept.alIyo, ,,,„y„,l,er, than fmall pieces of re fole'«nc

luia

J to

drawn all {

1 A L O G U E

: fame

3in-

t to

t id

eds

de-

m I

ret,
en,
the

without any other alteration fave
the declining the direfi: refiitude, fomctimes a very inlenfible mat-
ter towards one fide or another, and the pens moving its neb one
while fofter, another while flower, but with very fmall inequality.
And I think that it would in the fame manner write a letter, and
that thole frolUke penmen, who to (hew their command of hand,
without taking their pen from the paper in one fole ftroke, with
infinite turnings draw a pleafant knot , iftheywerein a boat that
did tide it along fwiftly they would convert the whole motion
of the pen, which in reality is but one fole line, drawn all towards
one and the fame part, and very little curved , or declining from
pcrfe<a reftitude, into a knot or flouriflh. And I am much pleafed
that S agrcdips hath helped me to this conceit : therefore let us go
on, for the hope of meeting with more of them, will make me the
m my attention.

S A G R. It you have a curiofity to hear fuch like fub til tics, which
occurr not thus to every one, you will find no want of them, cfpe-
cially in this particular of Navigation^and do you not think that a
witty conceit which 1 met with likcwife in the fame voyage, when I
obfervcd that the maft of the fliip, without either breaking or bend-
ing, had made a greater voyage with its round-top, that is with its
top-gallant,than with its foot^for the round top being more diftant-
from the centre of the Earth than the foot is , it haddcfcribed the
arch of a circle bigger than the circle by which the foot had pafTed.

Simp. And thus when a man walketh he goeth farther with
his head than with his feet*

Sagr. You have found out the matter your felf by help of
your own mother-wit : But let us not interrupt Sal^iatns.

OALv. it pleafeth me to fee Simplicius how he footheth up
nimlclf in this conceit, if happly it be his own, and that he hath not
borrowed it from a certain little pamphlet of conclufions, where
there are a great many more fuch fancies no lefs pleafant & witty-
It folio weth that we fpeak of the peicc ofOrdinance mounted per-
pendicular to the Horizon, that is , of a (hot towards our vertical
point, and to conclude , of the return of the ball by the fame line
unto the lame peice, though that in the long time which it is fe-
parated from the peice , the earth hath tranfported it many miles
towards the Eaft now it feemeth,that the ball ought to fall a like
diftance from the peice towards the Weft the which doth not
'^Ppen : therefore the peice without having been moved did ftay
^'^pe&ng the fame- The anfwer is the fame with that of the
^^Uing from the Tower and all the fallacy, and equivocati-
on confiftethin fuppofing ftill for orue, that which is in queftion j
Jor the Opponent hath it ftill fixed in his conceit that the
*>»ll departs from its reft , being difehargcd by the fire

V fram

Suhnltiet ffficf"
tntlj infipidf itoni"
cully, fpoken
taken from a eet"
r4/»Encyclopxdia.

ittflance a-
gMinft the dturndl
ntction of tht earthy
taken from the fhot '
^f^Peeciof Ordi*
nance perpendicit*
larlj.

The anftKT t»the

ctjsShoHf jhtw'mg
the «4jfti%'»ks y

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

3^4 G. G A L I L ^ u s, bis Syflcme.

from the piece ^ and the departing from the ftate of reft , cannot
be, unleffe the immobility of tlie Terrcftrial Globe beprefupl^'
fed, which is the conclulion of that was indifpute^ Therefore?
1 reply 5 thatthol'e who make the Earth moveable 5 anfwer , that
the piece, and the ball that is in it 5 partake of the fame motion
with the Earth j nay that they have this together with her bo^
nature ; and that therefore the ball departs in no other mannef
from its quiefcencc , but conjoyned with its motion about the ccn*
tre , the which by its pro)c£i:ioq upwards , is neither taken awayi
nor hindered ^ and in this manner following , the univerfal motion
of the Earth towards the Eaft, it alwayes kcepcth perpendicular
over the faid piece, as well in its rife as in its return. And the
fame you fee to enfue , in making the experiment in a (hip with
a bullet (hot upwards perpendicularly with a Croffe-bow , which
returneth to the fame place whether the fliip doth move , or frand
ftill. -.^
Another ar.ft,er S A G This fatisficth vcry well to all i but becaufe that I have
t<\thefam€ object' f^^^ ^^^t Stmplicius takcth pleafurc with certain fubtilties to
puzzle his companions , I will demand of him whether , fuppo-
fing for this time tliat the Earth ftanderh ftill , and the piece ere-
fted upon it perpendicularly, direfted to our Zenith , he do at all
queftion that to be the true perpendicular {hot , and that the ball
in departing, and in its return is to go by the fame right line>
ftill iuppofing all external and accidental impediments to be rC'
moved

S I M p. 1 underftand that the matter ought to fuccecd exaftly
in, tl^at manner.

S A G R. But if the piece were placed, not perpendicularly, but
inclining towards fome place , what would the motion of the ball j
be ? Would it go haply , as in the other (hpt j by the pcrpcndl-' '
cular line , and return again by the fame i 3 i ..k,

Simp. It would not fo do j but iffuing out of the piece , i^
would purfue its motion by a right line which prolongeth the e-*
reft perpendicularity of the concave cylinder of the piece , unleflW |
fo far as its own weight would make it decline from that crcStiOii
towards the Earth.

S A G U' So that the mounture of the cylinder is the regulator 0%
the motion of the ball , nor doth it , or would it move out of th^
line , if its own grarvity did not make it decline downwards. A*"^
ProieEls conti^ therefore placing the cylinder perpendicularly ^ and (hooting th^
Tthe'^ri ht'lZ upwards , it returneth by the fame right line downwards > he
tUtfolloiith *the caufe xhe motion of the ball dependent on its gravity isdowjv
dirtnien of th^ ward, by the fame perpendicular. Thj journey therefore of th« k
'^tt^' Z'lh 'tZ baHoutof the piece, continueth or prolongeth the reaitude^^ I
projicient, vhii*/f- perpendicularicy of thatfmall part of the faid journey 5 which I
made within the faid piece ^ is it not fo > S i m F' |

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

bat

4tb

Dialogue II.
S I M i'. So it is, in my opinion.

S A G R. Now imagine tlie cylinder to be crecied, and that th*e
Earth doch revolve about with a diurnal motion , carrying the
piece alop.g with it, tell me what fhall be the motion of the ball
vvithin the cylinder, having given tire >

S I M It fhall be a ftreight and perpendicular motion, the cylin-
der being ercSed perpendicularly.

S A G R. Conlidcr well what you fay : for I believe that it will
not be perpendicular. It would indeed be perpendicular , if the
Earth ftood ftill , for fo the ball would have no other motion but
that proceeding from the fire. But in cafe the Earth turns round,
the ball that is in the piece , hath likewife a diurnal motion , fo
that there being added to the fame the impulfe of the fire , it mo

T'/Jtf revolsstion
of the Earth
fofed , the ball /*
the piece ereSted

Vf^rUf 1 ? 1 r 1 . . ^1 .1 "t^ the piece ereSled

vccn n om the breech or the piece to the muzzle with two motions, perpendicuUrijy .
from the compofition whereof it cometh to palTe that the motion ^'^^'*'f move by a

TTii/^U 1 ritii . . , perpendicular^ hut

inaae by the centre ot the balls gravity is an inclinmg line. And amrtchriediine.
tor your clearer underftanding the fame , let the piece A C [/?/
P^g' 2.] be erccied , and in it the ball B i it is manifeft , that the
piece ftanding immoveable , and tire being given to it , the ball
Vvill make its way out by the mouth A , and with its centre , paf-
fing thorow the the piece , fliall have delcribed the perpendicular
lincBA, and it fhall purfue that reflitude when it is out of the
piece , moving toward the Zenith. But in cafe the Earth Ihould
move round 5 and confequently carry the piece along with it, in
the time that the ball driven out of the piece (hall move along
the cylinder , the piece being carried by the Earth , ftall paffe in-
to the fituation D E , and the ball B , in going off, would be at
the cornifli D , and the motion of the bals centre , would have
been according to the line B D , no longer perpendicular , but in-
chning towards the Eaft ; and the ball (as hath been concluded)
oeing to continue its motion through the air , according to the
direftion of the motion made in the piece , the faid motion fhilll
continue on according to the inclination of the line B D , andfo
fhall no longer be perpendiculac , but inclined towards the Eaft^
to which part the piece doth alfo move ^ whereupon the ball may
follow the motion of the EBrth,and of the piece. Now Stmplicius^
you fee it demonftrated , that the Range which you took to be
perpendicular, isnotfo.

Simp. 1 do not very well underftand this bufincfs j do you,

^ Sa l v. I apprehend it in part i but I have a certain, kind of
^^^Ple, which I wifh I knew how to exprefs. 1 1 feems to me, that
according to what hath been faid, if the Piece be erefted pcrpen-
^cuJar, and the Earth do move, the ball would not be to fall, as
^njtotle ^lidTycho will have it, far from the Piece towards the

V a Wc/lj

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

C. G A L I L u Sy his Syjlcmc.

Wcfi:,nor asyou woLiM have it, upon the Piece, but rather far
diftaiit co'vvards the Ealt. For according to your explanation,
woiiid have two motions, the which would with one confcnt cai'i^
it thitherward, to wit, the common morion of the Earth, vvhicJi
carrieth the Piece and the ball from C A towards E D h and the
lire which carrieth it by the inclined line B D, both motions to-
wards the Eaft, and therefore they arc fnpcrioiir to the motion oi
the Earth.

S A G R. Not To, Sir. The motion which carrieth the ball co-
wards the Eaft, Cometh all from the Earth, and the tire hath nb
part at all therein : the motion which mounteth the ball upwards,
is wholly of fire, wherewith the Earth hath nothing to do. And
that it is fo, ifyou give not fire, the ball will never go o jt of the
Piece, nor yet rife upwardb a hairs breadth ; as alfo if you make
the Earth immoveable, and give fire, the ball without any incli-
nation (hall go perpendicularly upwards. Th? ball therefore ha-
ving two motions, one upwards, and the other in gyration, of both
which the tranfverfe line B D is compounded, the impulfe upward
is wholly of fire, the circular cometh wholly from the Earth, and
is equal to the Earths motion : and being equal to it, the ball
maintaineth it felf all the way direfily over the mouth of the
Piece, and at laft falleth back into the fame : and becaufc it al'
ways obferveth the ereftion of the Piece, it appeareth alfo conti-
nually over the head of him that is near the Piece, and therefore
it appeareth to mount exaftly perpendicular towards our Zenith?
Of veitical point.

Simp. 1 have yet one doubt more remaining, and it is, that
regard the motion of the ball is very fwift in the Piece, it fee
not pofiible, that in that moment of time the tranfpofition of t
Piece fiomCA to AD fliould confer fuch an inclination upoff
the tranlV<rfe line C D, that by means thereof, the ball when ii
cometh afterwards into the air fliould be able to follow the cour6
of the Earftb

jSagii. You err upon many accounts ; and firft, the inciinatiori
of the tranfverfe line C D, 1 believe it is much greater than
take it to be, for 1 verily think that the velocity of the Ea^rthsinoi
tion, not oneJy under the Equinoctial, but in our paialel alfo,«i^
greater than that of the ball whilft it moveth in the Piece fo tha^
the interval C E would be abfolutely much bigger than the whole
length of the Piece, and the inclination of the tranfverfe line corr
^^c^uently bigger than half a right angle : but be the velocity o,
the Earth more, or be it lefs, in comparifon of the velocity of th^
fire, thk imports nothing j for if the velocity of the Earth be fmaH^
and cpnfcquently the inclination of the tranfverfe line be litcli'
alfo svthcre ia then alfo need but of little inclination to make the

ball

Dialogue* I L

ball lufpead it felf in its range dirc£t]y over the Piece. And in 1
word, if you* do but attentively coniider, you will comprehend,
that the motion of the Earth in transferring the Piece along with
it from C A to E D? conferreth upon the traniverle line C D, fo
much of little or great inclination, as is required to adjuft the
range to its perpendicularity. But you err, fecondly, in that you
referr the taculty of carrying the ball along with the Earth to the
impulfe of the fire, and you run into the fame error, into which
Siilifiatf^^ but even now fcemed to have fallen ^ for the faculty
of following the motion of the Earth, is the primary and perpetual
motion, indelibly and infeparably imparted to th^ faid ball, as to a
thmgterreftrial, and that of its own nature doth and ever fliall
pofTefs the fame.

Salv. Let us yield, 5/>/^//f/;^5 for the buiinefs is juft as he
faith. And now from this difcourfe let us come to underftand the
reafon of a Vcnatorian Problem, of thofe Fowlers who with their
guns (hoot a bird flying , and becaufc I did imagine, that in regard
the bird flicth a great pace, therefore they fliould aim their fliot far
from the bird, anticipating its flight for a certain fpacc, and more
or lefs according to its velocity and the diftance of the bird, that
fo thebulkthaftingdireSily to the mark aimed at, it might come
to arrive at the felf fame time in the fame point with its motion,
and the bird with its flight, and by that means one to encounter
the other : and asking one of them 5 if their praSife was not fo
to do i He told me, no j but that the flight was very eafie and
certain, and that they took aim juft in the fame manner as if they
tad ftiot at a bird that did lit ftill r that is, they made the flying
bird their mark, and by moving their fowling-piece they followed
keeping their aim ftill full upon her, ttll fuch time as they let
"y>and in this manner (hot her as they did others fitting ftill. " It is
neceflary therefore that that motion, though flow, which the fowl-
*og-piece maketh in turning and following after the flight of the
l>ird do communicate it felf. to the bullet alfo, and that it be joyned
with thajt of the fire ^ fo that the ball hath from the fire the mo-
tion direftly upwards, and from the concave Gylinder of the barrel
the declination according to the "flight of the Bird, juft as was faid
before of the fliot of a Canon *, where the balV receivcth frotn the
fire a virtue of mounting upwards towards^ the Zenith, and from
the motion of the Earth its winding towards the Eaft, and of both
^aketh a compound motion that foUoweth the courfe of the
Sarth, and that to the beholder feemeth oiiely to go direftly up-
^^rds, and return again downwards by the fame line. The hold-
^"8 ^'^^efore of the gun continually direacd towards the mark,
"^^xT J ^^^^ right, and that you may keep your gun di-
rected to tke mark, m cafe the mark ftands ftill, you muft alfo hold

your

The manner how
FoTvlers fhoothhrds

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2°K.B. 9,163

138

G G

A L I L U S

fiam I hi fmts if
g'tM ^1"! miire
towards the Ncrih
*itd Smth.

Sjfleme.

yoar g»n ftill,aiid if die mark ftall movc,tlie gun muft be kept upon
T*, ..ft^er t. the mark by movnig. Ar.d upon this depcndeth the proper anlwer

-^^g"'"^'", f'0.n the fhot of , Canon, at the
mark placed towards the South or North : wherein is aliedsed,
that it the Earth (hould move, the fliots would all range Weft-
ward of the mark, becaufe that in the time whilft the ball, bcinff
tore d out of the Piece, goeth through the air to the mark, the laid
mark benig earned toward the Eaft, would leave the ball to the
Wcftward. 1 anfwer therefore, demanding whether if the Ca-
non be aimed true at the mark, and permitted fo to continue it
will conftantly hit the faid mark, whether the Earth move or ftand

I f T i. a *™ ''''""'^ not at all, for if

the mark doth ftand Hill, the Piece alfo doth ftand ftill and if it
being tranlported by the Earths motion, doth move, the Piece doth
-alfo move at the lame rate and, the aim maintained, the fliot
proveth always true, as by what hath been faid above, is mani-

S A G R. Stay a little, I entreat you, Sahiatus, till I have pro-
pounded a certain conceit touching thefe (hooters of birds flying,
whole proceeding I believe to be the lame which you relate, and
believe the efFeft of hitting the bird doth likewife follow : but yet
I cannot think that aft altogether conformable to this of fliooting
in great Guns, which bught to hit as well when the piece and mark
moveth, as when they both ftand ftill ; and thefe, in my opinion
are the particulars in which they dilagrec. In fliooting with a
great Guii both it and the mark move with equal velocity, beine
both tranlported by the motion of the Terrcftrial Globe • and al
beitfonietimes the piece being planted more towards the Pole
than the mark, and coulequently its motion being fomewhat flow-
er than the motion of the mark, as being made in a leffer circle
Uicha difference is in(enfible, at that little diftance of the piece
from the mark ; but in the fliot of the Fowler the motion of the
FowJi^g-piece wherewith it goeth following the bird, i, very flow
m compaalon of the flight of the faid bird i whence me thinks it
fliould follow, that that fmall motion which the turnihe of the
Birding-piece confmeth on the bullet that is within it, cannot,
when it IS once gone forth of it, multiply it felf in the air, untill it
come toequal the velocity of the bitds flight,fo as thatthe faid bullet
ihould always keep direft upon it : nay, ine thinketh the bird
Would anticipate it and leave it behind. Let me add, that in this
aft, the air through whjch the bullet is to pals, partaketh not of the
motioQo^ the bird whereas in the cafe of the Canon, both it,
the mark,and f\y^ intermediate air, do equally partake of the com-
mon diurnal motion. So that the true caufe of the Marks-man
bis iiittiDg the mark, as it fliould feem, moreover and befides the

following

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2°K.B. 9,163

DiALOOliE. IL

following the birds flight with the piece, is his fomewhat anticipa-
ting it, taking his aim before it , as alfo his fliooting (as I believe)
not with one bullet, but with many fmall balls Ccalled (hot) the
which Icattering in the air poffef? a great fpacc , and alfo the ex-
treme Yfilocity wherewith thefe (hot, being difcharged from the
Gun, go towards the bird.

S A L V. . See how far the winged wit of Sagredus anticipateth,
and out-goeth the dulncfs of mine ^ which perhaps would have
light upon thefe difparities, but not without long ftudie. Now
turning to the matter in hand, there do remain to be cohfidered
by us the fliots at point blank, towards the Eaft and towards the
5 the firft of which, if the Earth did move, would always
happen to be too high above the mark, and the fecond too low ,
waimuch as the parts of the Earth Eaftward, by reafon of the di-
urnal motion, do continually dcfcend beneath the tangent paralel
to the Horizon, whereupon the Eaftern ftars to us appear to afcend;
and on the contrary, the parts Weftward do more and more af-
cend, whereupon the Weftern ftars do in our feeming delcend :
and therefore the ranges which are leveled according to t'he faid
tangent at the Oriental mark, (which whilft the ball' pafleth
along by the tangent dcfcendeth) fliould prove too high, and the
Occidental too low by means of the elevation of the mark^ whilft
the ball pafleth along the tangent. The anfwer is like to the reft :
for as the Eaftern mark goetk continually defcending, by reafon
of the Earths motion, under a tangent that continueth immove-
able ^ ii) likewife the piece for the fame reafon goeth continually
inclining I, and with its mounture purfuing the faid mark : by
which means the fliot proveth true.

But here I think it a convenient opportunity to give notice of
certain conceflions, which are granted perhaps over liberally by
the followers of Copirnicus unto their Adverfaries ■: 1 mean of
yielding to them certain experiments for fure and certain, which
yet the Adverfaries themfelves had never made tryal of : as for
example, that of things falling from the round- top of a (hip whilft
It is m motion, and many others ^ amongft which I verily believe,
that this of experimenting whether the (hot made by a Canon to-
wards the Eaft proveth too high, and the Weftern /hot too low,
IS one : and becaufe I believe that they have never made tryal
thereof, I dcfire that they would tell me what difference they
^hink ought to happen between the faid fliots, fuppofing the Earth
Moveable, or fuppofincr it moveable; and let Simplicius for this
t"!^^ anfwer fo/them." - . •

a I M 1- I will not undertake to anfwer id confidently as another
'"j^lligent perhaps might do ; but fliall fpeak what thus upon
oieluddcQl think they would reply i which is in cfifca the famrf

with

The anfwer to the
^yfraumeMt taken
from the (hots at
point hlatick^ to-
Tvardi the Eafi ($•

mft.

Thefoll$%9trs of
Copernicus too
freely admit cer-
tain fropofitiontfor
trucy which mre
very doubtfHH*

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2°K.B. 9,163

i6o

how much the r4«-

tmght tc vary from
the msrke , the
£iirths motion h"
tng grdnted.

G. Galilsus, his SjJIeme.

with that which hath been faid already, namely, that in cafe the
Earth (hould move, the ftiots made Eaftward would prove too
high, &c. the ball, as it is probable, being to move along the tan-

S A L V. But It I fliould fay, that fo it falleth out upon triall,
how would you cenfure me f

Simp. It is neccffary to proceed to experiments for the pro-
ving of it.

S A L V. But do you think, that there is to be found a Gunner fo
skilful, as to hit the mark at every (hoot, in a diftancc of o/.g. five
hundred paces ?

S 1 M ^. No Sir j nay I believe that there is no one, how good a
marks-man focver that would promifc to come within a pace of
the mark,

S A L v. How can we then, with fliots fo uncertain, afTurc out
felves of that which is in difpute ?

Simp. We may be affured thereof two waycs i one, by mra-
kingmany fliots j the other, becaufe in refpeftof the great velo-
city of the Earths motion , the deviation from the mark would in
my opinion be very great.

S A L V. Very great, that is more than one pace j in regard that
the varying fo much, yea and more,is granted to happen ordinarily
even in the Earths mobility.

Simp. I verily believe the variation from the mark would be
more than fo.

S A t V. Now I defire that for our fatisfafiion we do m^c thus
in grolTc a flight calculation, if you confent thereto, which will
ftand us in ftead likewife (if the computation fuccecd as I expeft)
for a warning how we do in other occurrences fuffer our felves, as
the faying is, to be taken with the enemies fliouts, and furrcndcr
up our belief to what ever firft prefents it felf to our fancy. And
now to give all advantages to the Peripateticl{s and Tychonic^f^
let us fuppofc our felves to be under the Equinofiial, there to flioot
a piece of Ordinance point blank Eaftwards at a mark five hun-
dred paces off. Firft, let us fee thus (as 1 faid) in a level, what
time tJbe fliot after it is gone out of the Piece takcth to arrive at
the mark j which wc know to be very little, and is certainly no
more than that wherein a travailer walketh two fteps , which alfo
is Icfs than the fccond of a minute of an hour; for fuppofing
that the travailer walketh three miles in an hour, which arc nine
thouCand paces, being that an hour containes three thoufand, fi^
hundred fccond minuter, the travailer walketh two fteps and afl
half in a fccond, a fccond therefore is more than the time of the
balls motion. And for that the diurnal revolution is twenty four
hours, the Weftcrn horizon rifeth fifteen degrees in an hour, that

is?

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2°K.B. 9,163

I A L O G U E

i6i

Is, fifteen fi I ft minutes of a degree, in one firft minute of an hoiiri
that is, fifteen feconds of a degree, in one fccond of an hour ^ and
becaufe'one fccond is the time of the (hot, therefore in this time
theWeftern horizon rifeth fifteen feconds of a degree, and fo
much likewile the mark ; and therefore fifteen feconds of that cir-
cle, whofc femidiamcter is five hundred paces (for fo much the di-
ftance of the mark from the* Piece was fuppofed.^ Now let us
look in the table of Arches and Chords (kc here is Copernicm his
book) what part is the chord of fifteen feconds of the femidiamc-
ter, that is, five hundred paces. Here you fee the chord (or fub-
tenfe) of a firft minute to be Icfs than thirty of thofe parts, of
which the femidiameter is an hundred thoufand. Therefore the
chord of a fecond minute fliall be lefs then half of one of thofc
parts, that is lefs than one of thofe parts, of whichthe femidiame-
ter is two hundred thoufand i and therefore the chord of fifteen
conds jhall be lefs than fifteen of thofe fame two hundred thoufand
parts j but that which is lefs than (a) fifteen parts of two hun-
dred thoufand, is alfo more than that which is four centefmcs of
five hundred j therefore the afcent of the mark in the time of the
balls motion is leffe than four centefmes, .that is, than -one twenty
fifth part of apace, it fliall be therefore (J>) about two inches :
And fo much confequently fliall be the variation of each Weftern
fliot, the Earth being fuppofed to have a diurnal motion. Now if I
fliall tell you, that this variation (I mean of falling two inches fliort
of what they would do in cafe the Earth did not move) upon tri-
all doth happen in all ftiots, how will you convince me SimpliciuSi
(hewing me by an experiment that it is not fo ? Do you not fee
that it is impoflible to confute me, unlefs you firft find out a way
to flioot at a mark with fo much cxaaneflTe, as never to miffe an
hairs bredth ? For wh.ilft the ranges of great fliot confift of diflfc-
^^ent numbers of paces, as de fa6io they do, I will affirm that in
each of thofe variations there is contained that of two inches cau-
fed by the motion of the Earth.

, S A 6 R.. Pardon mc^Sahiatm^ you are too liberal. For I would
tell the Peripateticl{S, that though every fliot fliould hit the very
centre of the mark, that fliould not in the Icaft difprove the motion
of the Earth. For the Gunners are fo conftantly imployed in le-
velling the fight and gun to the mark, as that they can hit the fame,
nptwithftanding the motion of the £arth. And ^ fay, that if the
Earth Ihould ftand ftill, the fliots would not prove true i but the
Accidental would be tddlow, and the Oriental too high : now let
SmfUciHs difprove me if he can.

Sal v. This is a fubtilty worthy of Sagredus : But whether
this variation be to be obferved in the motion, or in the reft of the
Earth, it niuft needs be very fiiiall, it muft needs be fwallowed up

X in

(4) That is, in
plainer tcrmes the
fra<5lion -jTTrr^, is
more than the fra-
TTTT^/or di-
viding Che denomi-
nators by their no-
minaiors, and the
firlt produccth
MHSf the odier
but 12500,

{b) Ic fliall be
ncer 2' inches, ac»
counting the pace
to be Geometrical,
containing 5 foot.

// is dtmonfir^'
tid with iredtfub-
ttlty , thdt the
Earths motion fup'
pofedy Canon (hot
ought not to varf
mors than in refi.

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2°K.B. 9,163

\6i

It U rcq-tl'jte to
be very CAm»r:Hi in
Admitting expe*-i'
Wems for trUf, to
thop r»ho never
tried them.

Exp :ritne fits 4rd
^^g^ttmems againfi
the Earths motion
feem fo far co?i-
cludiMjr^ as they lie
^'d under tqtii'

G. G A L I L u s, his Sy^lcmt.

in thofe very great ones which fundry accidents continually pre
duce. And all this hath been fpoken and granted on good grounds .
to SimpliciHS^ and only with an intent to advertile him how much
it impoi tcth to be cautious in granting many experiments for true
to thofe who never had tried them, but only eagerly alledged them
)uft as they ought to be for the ierving their purpol'e : This is fpo-
ken, I fay, by way of furpluffage and Corollary to Simplicim^ for
the real truth is, that as concerning thefe fhots, the (lime ought ex-
aftly to befall afwell in the motion as in the reft of the Terreftrial
Globe j as likewife it will happen in all the other experiments
that cither have been or can be produced, which have at tirft blufli
fo much femblancc of truth, as the antiquated opinion of the
Earths motion hath of equivocation.

Sag r. As for my part I am fully fatisficd , and very well un-
derftand that who fo (hall imprint in his fancy this general com-
munity of the diurnal converfion amongft all things Terreftrial,
to all which it naturally agrceth, afwell as in the old conceit of its
reft about the centre, (hall doubtlcfTe difcern the fallacy and equi-
voke which made the arguments produced feem concluding.
There yet remains in me fome haefitancy (as I have hinted be-
fore) touching the flighfof birds j the which having as it were an
animate faculty of moving at their pleafure with a thoufand mo-
tions , and to ftay long in the Air feparated from the Earth , and
therein with moft irregular windings to go fluttering to and again,
1 cannot conceive how amongft fo great a confufion of motions
they fliould be able to retain the firft commune motion \ and in
what manner , having once made any ftay behind , they can get
it up again , and overtake the fame with flying , and keep pax:c
with the Towers and trees which hurry with fo precipitant a courfe
towards the Eaft , I fay fo precipitant , for in the great circle of
the Globe it is little Icfle than a thoufand miles an hour , whereof
the flight of the fwallow I believe makes not fifty.

Sa L V. if the birds were to keep pace with the courfe of the
trees by help of their wings , they would of neceffity flic very faft j
and if they were deprived of the univcrfal ronverfion , they would
lag as far behind j and their flight would feem as furious towards
the Weft, and to him that could difcern the fame , it would
much exceed the flight of an arro\y ^ but I think we could not be
^ble to perceive it , no more tljan we fee a Canon bullet, whifft
driven by the fury of the fire , it flieth through the Air : But the
truth IS that the proper motion of birds , .1 mean of their flight,
hath nothing to do with the univcrfal motion , to which it is nei-
ther an help , nor an hinderance j and that which maintaineth
the faid motion unaltered in the birds , is the Air it felf , thorough
which they flic , which naturally following the Vertigo of th^*

Earth

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2°K.B. 9,163

DiALpGllF. IL

Earth , like as it carrieth the clouds along with it, fo it ti anfporteth
birds and every thing clfe which is pendent in the fame^ in lb much
that as to the bufincffe of keeping pace with the Earth , the birds
need take no care thereof , but for that work might fleep perpe-
tually.

S A G R. That the Air can carry the clouds along^ W ith it , as
ocmg matters eafie for their lightnclTc to be moved and deprived
oi all other contrary inclination , yea more, as being matters that
partake alio of the conditions and properties of the Earth , I com-
prehend without any difficulty h but that birds, which as having
lite , may move with a motion quite contrary to the diurnal , once
having furceafed the faid motion , the Air fhould rcftore them to
itj ieems to me a little ftrange, and the rather for that they are folid
and Weighty bodies and v^rithal, we fee ^ as hath been faid, ftoties
. other grave bodies to lie unmoved againft the impetus of the
^kL ' ^^^y fufFer themfelves to be overcome thereby ,

tlity never acquire fo much velocity as the wind vvhich carrieth
them.

S A L V. We afcribe not fo little force , Sagr^dus^ t<S the moved
Air 5 which is able to move and bear before it fliips full fraught,
to tear up trees by the roots , and overthrow Towers when it
moveth fwiftly and yet we cannot fay that the motion of the
Air in the fe violent operations is neer fo violent, as that of the
diurnal revolution.

Simp. You fee then that the moved Air may alfo cotinue the
motion of projefts , according to the Doftrinc of Arijlotle ^ and
it feemed to me very ftrange that he fhould have erred in this
particular.

b^lV^' ^t may without doubt, in cafe it could continue it felf,
ut hk as when the wind ceafing neither fliips go on , nor trees are
olown down , fo the motion in the Air not continuing after the
Itone is gone out of the hand , and the Air ceafing to move , it
tollowcth that it muft be fomething elfe befides the Air that ma-
^^th the projefts to move.

Sim p. But how upon the winds being laid , doth the fliip ccafc
to move >' Nay you may fee that when the wind is down, and
the iails furl'd , the vcfTel continueth to run whole miles.

S A L V. But this maketh againft your felf SimfliciHS , for that

^ne wind being laid that filling the fails drove on the fliip , yet ne-

J^rthelefTe doth it without help of the medmm continue its
courfe.

carried p ^^^^ be faid that the water was the medium which
>ea torward the fliip , and maintained it in motion.
A L V. :ic ^^^Yit indeed be fo affirmed, if you would fpeak

nuue contrary to truth •, for the truth is , that the water , byrea-

X a fon

1^4

. The great fc/i'
tit J for which they
are much to ht en-
vied who ferfwaie
tbunfelves
they k*:orp
thing*

G. G A L I L u s , his Sjfleme.

ion of its great rcfiftance to the divifioii made by the hull of the
Ihip, doth with great noife refift the fame 5 nor doth it permit it
of a great while to acquire that velocity which the wind would
confer upon it , were the obftacle of the water removed. Per-
haps Sim^licim you have never confidered with what fury the
water befets a bark , whirii it forceth its way through a ftanding
water by help of Oars or Sails : for if you had ever minded that
cffeft 5 you would not now have produced fuch an abfurdity.
And 1 am thinking that you have hitherto been one of thole who
to find out how fuch things fucceed , and to come to the know-
ledg of natural effefts , do not betake thcmfelves to a Ship , a
Crolfe-bow , or a piece of Ordinance , but retire into their ftu'
dies , and turn over Indexes and Tables to fee whether JriSiotle
hath fpoken any thing theieof, and being alTured of the true
fenie of the Text , neither defire nor care for knowing any
more

S A G R. This is a great felicity , and they are to be much
vied for it. For if knowledg be defired by all , and if to be v/iM
^^^^ be to think ones (elf fo , they enjoy a very great happinefle , for
That that they may perfwade themfelves that they know and underftani
'^"'^ all things 3 in fcorn of thofe who knowing, that they underftand
not what thefe think they underftand , aiad canfequently feeking
that they know not the very leaft particle of what is knowable,
kill themfelves with waking and ftudying , and confume their dayij
in experiments and obfervations. But pray you let us return t
our birds ^ touching which you have faid , that the Air being mo*
ved with great velocity , might reftore unto them that part of thc
diurnal motion which amongft the windings of their flight tl^f \
might have loft j to which I reply , that the agitated Air feemeth
unable to confer on a folid an4 grave body , fo great a velocity afi
its own : And becaufe that of the Air i§ as great as that of tbc
Earth / I cannot think that the Air is able to make good the loiS
of the, bifds retardation in flight. \' [:di

'S A L V. Your difcourfe hath in it much of probability , and to
ftick at trivial doubt? is not for an acute wit ^ yet neverthelefle th«
probability being removed , I believed that it hath not a )ot moffl
force than the others already confidered and refolved.

S A o It is moft certain that if it be not necelTarily condi^'
dent 5 its efficacy muft needs be juft nothing at all , for Hi^
oncly when the conclufion is neceffary that the opponent ^lath no*
tiling to alledg on the contrary.

S ^ 1^ V. Your making a greater fcruplc of this than of the otb^f t
inftances dependeth, if I miftakc not, upon the birds being aiji' ^'
mated , and thereby enabled to ufc their ftiength at pleafurc
gainft the primary niotion io-brcd in terrene bodice : like as

example?

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D I A L b G U E I I.
example, we fee them whirft they are alive to fly upwards, a thing
altogether impoffible for them to do as they are grave bodies y
whereas being dead they can onely fall downwards *, and there-
fore you hold that the reafons that are of force in all the kinds ot
projeds above named, cannot take place in birds : Now this is
very true ^ and becaufe it is fo , Sagredtis that doth not appear
to be done in thofe projefis , which we fee the birds to do. For if
from the top of a Tower you let fall a dead bird and a live one,
the. dead bird (hall do the fame that a ftone doth , that is , it (hall
firft follow the general motion diurnal , and then the motion of
defccnt , as grave , but if the bird let fall , be alive , what ifhall
hinder ir, (there ever remaining in it the diurnal motion) fropi
foaring by help of its wings to what plac^ of the Horizon it (hall
pleafc ? and this new motion , as being pecuKar to the bird, and
^ot participated by us , muft of neceflity be vifible ^o us ^ and if
it be moved by help of its wings towards the Weft , what ftiall
hinder it fiom returning with a like help of its wings unto tlif
Tower. And, becaufe, in the laft place , the bird swending its
flight towards the Weft was no other than a withdrawing from
the diurnal motion, (which hath, fupppofe ten degrees of velocity)
one degree onely , there did thereupon remain to the bird.^vhirft
it: was in its flight nine degrees of velocity, and fo fopn as it did
alight upon the the Earth , the ten common degrees returned to it|
to which , by flying towards the Eaft it might adde one, s^iid witl^
thofe eleven overtake the Tower. And in thort , if we well con-
fider , and more narrowly examine the eflfefts of the flight of
birds , they difterfrom the projeSs (hptor thrown to any part pf
the World in nothing, fave on^ly th^t the prpjeSs are moved ai>
external piojicjent , ^nd the birds by aq iptern^il principle. A^^d
here for a final prpof of ;he nuUicy of all ^he experiments J^efpr^
^lledge4 , 1 wngcivp i^ now g . %im ^t}4 pl^pe convepien; to
deqionftvate a way hpw to fp^ike an ex^^ trial of them all.
Shut your felf up \vir)i fp^iie friend ifl the? gr^nd Cabbin hefweeq
the deck$ of fpmc large Ship, there procure gnats, flics, and
fuch other fmall wipged creatijres : get alfo a great tub (or
other veffd) full of water, and within it put certain fiflies i le^
alfo a certain bottle bq hung i^p, which drop by drop Ictte^h fortfe
its w^ter into aaother bottle placed underneath, having a narrow
neck : aiKl, the Ship lying ftill, obferve diligently how thofe fmall
Winged animals fly with hke vploci^y towards j^.U parts of the Ca-
W howtheflfliesfwiminditfpfently towards all fides j and how
^^ diftiUing drops all fall into the bottle pUced underneath. Ap4
rafting any thing towir4^ your friend, you need not throw it with
more force one way then anotl)er, provided the diftanccs be equal:
«4 Icapiag, as the f^tyipg is, with ypur feet clofc4, you wiH rcacji

is'

7 he anfteer f#
the argument f4-
ken from

of lirds cpmr^ry
to the motitHoftke
Earth,

%4n experimfnt
with jvhich alone
i4 fhewn the nudity
of nil the ohjeSf
ons prod/tced a*
gain^ the motion
of the earth.

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2°K.B. 9,163

166 G. G A L I L ^ a s, his Sy^lmc^

far one way as another. Having obferved all thefe particular's
though no man doubteth that lb long as the veffel ftands ftillj they
ought to fucceed in this manner ^ make the Ship to move wirh:j
what velocity you pleafc , for (fo long as the motion is uniforme,
and not fluftuating this way and that way) you (hall not difceni^
any the leaft alteration in all rhe forenamed efFefis , nor can you
gather by any of them whether the Ship doth move or fiand ftilL
In leaping you fliall reach as far upon the floor, as before , nor for ]
that the Ship moveth fhall you make a greater leap towards the
poop than towards the prow , howbeit in the time that you ftaid
in the Air^the floor under your feet (hall have run the contrary way
to that of your jump *, and throwing any thing to your companion .
you lhall not need to caft it with more ftrength that it may reachJ
him, ifhefliall be towards the prow, and you towards the poop J
then if you ftood in a contrary ficuation', the drops fliall all diftill
as before into the inferiour bottle, and not fo much as one (hall
fall towards the poop, albeit whil'd the drop is in the Air, theShipiJ^i
fliall have run many feet ^ the Fifties in their water fliall not fwiiiil
with more trouble towards the fore-part, than towards the hinderl
part of the tub 5 but fliall with equal velocity make to the bai«
placed On any fide of the tub j and laftly , the flies and gnata|
fliall continue their flight indifferently towards all parts 5 non
fliall they ever happen to be driven together towards the fide o^
the Cabbin next the prow , as if they were wearied with fol^
lowing the fwift courfc of the Ship , from which through theiil
fufpenfion in the Air, they had been long feparated j and ifl
burning a few graines of incenfe you make a little fmcJkc3
you fliall fee it afcend on high, and there in manner of a cloucfl
fufpend itielf, and move indifferently, not inclining more to on^
fide than another : and of this correfpondence of eflPefts the cauf«
is for that the Ships motion is common to all the things contained^
in it, and to the Air alfo , I mean if thofe things be fliut up in the^
Cabbin : but in cafe thofe things were above deck in the open Air^'^
and not obliged to follow the courfe of the Ship, diflTcrences more^l
or lefle notable would be obferved in fome of the fore-named ef-- i
(c&s, and there is no doubt but that the fmoke would ftay behind^J
as much as the Air it felf h the flies alfo, and the gnats being hin-'^
dered by the Air would not be able to follow the motion of the
Ship, if they were feparated at any diftanee from it. But keeping
neer thereto, becaufe the Ship it felf as being an unfraftuous Fa-
^*^ck, carrieth along with it part of its neercfl: Air, they would !
fol'ow the faid Ship without any pains or difficulty. And for the" ■
like reafoti wc fee fomecimes in riding pofl:, that the troublefomC
: s, harfe. ^fid * hornets do follow the horfcs flying fometimes to one,
fomctifaes to another part of the body, but in the falling drops

the

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Dialogue. 1 1. 1^7

^ac difference would be very fniall j and in the falts, and pfojefti-
011s ot grave bodies altogether imperceptible.

S A G R. Though it came not into my thoughts to make trial! of
thcle obfcrvations, when I was at Sea, yet am I confident that they
wiliiucceed in the fame manner, as you have related ^ in confirma-
tion of which 1 remember that being in my Cabbin 1 have asked
an hundred times whether the Ship moved or flood ftiH • and
fometimes 1 have imagined that it moved one way, when it fteered
quite another way. I am therefore as hitherto fatisfied and con-
vinced of the nullity of all thofe experiments that have been pro-
duced in proof of the negative part. There now remains the ob-
jeSion founded upon that which experience (hews us, namely, that
^ iwift Vertigo or whirling about hath a faculty to extrude and
Quperfe the matters adherent to the machine that turns round ^
vvheieuponmany were of opinion, and Ftolomy amongft the reft,
^atif the Earth fliould turn rpimd with fo great velocity, the
ftones and creatures upon it fliould be toft into the Skie, and
^hat there could not be a morter ftrong enough to faftcn buildings
fo to their foundationis, but that they would likewifc fufFer alike
extrufion.

Salv. Before I come to anfwer this objeftion, I cannot but
take notice of that which I have an hundred times obferved, and
not without laughter, to come into the minds of moft men fo foon
^s ever they hear mention made of this motion of the Earth, which
i« believed by them fo fixt and immoveable, that they not only ne-
ver doubted of that reft, but have ever ftrongly believed that all
other mcn afwell as they, have held it to be created immoveable,
and fo to have continued through all fuccecding ages : and being rhefinpidity of
ietled in this pcrfwafion, they ftand amazed to hear that anyone fome thxt thitAjht
fliould grant it motion, as if, after that he had held it to be immo- ^J*'''^ tohavtbc
vcat)ie, ne had iondly thought it to commence its motion then Pythagoras hgan
(and not till then) when'Fythagor^ (or whoever clfe was the firft to^jjirmi that a
Winter of its mobility ) faid that it did move. Now that {uch a foQ- '
Ii(h cx)nceit (1 mean of thinking that thofe who admit the motion
of the Eaxth, have firft thought it to ftand ftill from its creation,
"ntillthe timeof Pythagoras^ and have onely made it moveable
^cer that Fythagot as cdccmcd it fo) findeth a place in the mindes
of the vulgar, and men of fliallow capacities, I do not much won-
but that fuch perfons as Arijiotle and Ptolomy fliould alfo
run into this childifli miftake, is to my thinking 'a more admirable
^nd unpardonable folly.

i V ^^^^ '^^'ieve then, SahiatH^.thd^tTtolomy thought, that
n his Difputacion he was to maintain the ftability of the Earth
a\u ^^^^ P^^'o^s, as granting it to have been immoveable, un-
^^^^^^^ of Pythagoras , did affirm it to have been but then

made

i6S

Pc I'^my ftem to
confute the mobtli'
tj of the E'*rth a-
g*\njt thoft rfr?o
thought thdt it hd'
vt»f a long time
fioodnili, did be-
j^in to move in the
j/wffl/ Pythagoras

G. GALiLiT:us, his Sjfleu^e.

made moveable, when the [siid Pyih ago r as afcribed unto it tnO'
tion.

S A L V. We can think no other, if we do but confider the way
he taketh to confute their aflertion the confutation of which
confifts in the demolition of buildings, and the tofling of ftoncS)
living creatures and men themfelvcs up into the Air. And be
caufc fuch overthrows and extfulions cannot be made upon boil*
dings and men, which were not before on the Earth, nor can mcA
be placed, nor buildings erefted upon the Earth, unleffe when it
ftandethftiir, hence therefore it is cleer, that Ftolomy argueth^'
gainftthofe, who having granted the ftability of the Earth fot
fome time, that is, fo long as living creatures, ftones, and Mafops
were able to abide there, iind to build Palaces and Cities, make it
afterwards precipitately moveable to the overthrow and deftrufli'
of Edifices, and living creatures, &c. For if he had undertook to
difpute againft fuch as had afcribed that revolution to the Eartk
from its firft creation, he would have confuted them by faying'
that if the Earth had alwayes moved, there could never have beef ,
placed upon it either men or ftones , much lefs could buildings |
have been erefted, or Cities founded, &c.

S I M p. I do not well conceive thefe Arifiotdick^ and FtP^^
maich^ inconveniences.

S A L v. Ftolomey either argueth againft thofe who have cftceiJi'
ed the Earth always moveable j or againft fuch as have held th*^
it ftood for fome time ftill, and hath fince been fet on moving'
If againft the firft, he ought to fay, that the Earth did not always
move, for that then there would never have been men, animals, ^
edifices on the Earth , its i/ertigo not permitting them to M
thereon. But in that he arguing, faith that the Earth doth nO^
move, becaufe that beafts, men, and houfcs before plac'd on tl^
Earth would precipitate, he fuppofeth the Earth to have been od^^
in fuch a ftate, as that it did admit men and beafts to ftay, aPj'
build thereon j the which draweth on the confequence, that
did for fome time.ftand ftill, to wit, was apt for the abode of ^
nimals and ereftion of buildings. Do you now conceive wha^ '
Would fay?

Simp. I ^ do not : but this little importcth to th*

merit of the caufe j nor can a fmall miftake of Ftolomey-, coW
mitted through inadvertcncic be fufficient to move the Earths
when it is immoveable. But omitting cavils, let us come to
fubftj^nceof the argument, which to me feems unanfwerable.

S A L v. And I, Slmpliciiis-^ will drive it home, and re-inforcc
by (hewing yet more fenfibly , that it is true that grave bo^i^^
turn d v^ith velpcity about a fettled centre, do acquire an imf^^^
of moving, and ^^^^ding to a diftance from that centre, eV^

th^^

Dialogue I L
thciuvhcn they arc ia a ftate of having a propenilon of moving
naturally to the fame. Tie a bottle that harh water in it, to
the end of a cold, and holding the other end faft in your hand,
^nd making the cord and your arm the femi-diameter, and the
knitting of' the (houlder the centre, fvving the bottle very faft a-
l^out, fo as that it may defcribe the circumference of a circle,
whichj whether it be parallel to the Horizon, or perpendicular to

or any wav inclined, it fhall in all cafes follow, that the wa-
ter will not fall out of the bottle ' nay, he that (hall fwing ic^
ihall find the cord always draw, and ftrive to go farther from the
ihoulder. And if you bore a hole in the bottom of the bottle,
youfliall fee the water fpout forth no lefs upwards into the skie,
than laterally, and downwards to the Earth ^ and if inftcad of wa-
l^^ijyoa fliallput little pebble ftoncs into the bottle, and fwing it

the fame manner, you fliall find that they will ftrive in the like
manner againft the cord. Andlaftly, we fee boys throw ftones
^gteat way, by fwinging round a piece of a ftick, at the end of
^vhich the ftone is let into a flit (which ftich^ is called by them a
fl^^'i'-y) all whrch are arguments of the truth of the conclufion^
to uit that the i/crtigo or fwing confer reth upon the moveable,
a motion towards the circumference, in cafe the motion be fwift :
and therefore if the Earth revolve about its own centre^ the mo-
tion of the fuperficies , and efpccially towards the great circle,
as being incomparably more fwift than thofe before named, ought
to extrude all things up into the air.

Sim p. The Argiunent feemeth to me very well proved and
Enforced j and I believe it would be an hard matter to anfwer and
overthrow it.

Salv. Its folntion depcndeth upon certain notions no lei's
known and believed by you, than by my felf : but becaufe they
come not into your mind, therefore it is that you perceive not the
anfwer j wherefore, without telling you it (for that you know the
f^nie already) 1 fliall with onely affiftingyour memory, make you
to refute this argument.

Simp. I have often thought of your way of arguing, which
hath made me almoft think that you lean to that opinion of Fla-
to, Q^dd aojimm fare fit quoddam remimfci therefore I intreat
you to free me from this doubt, by letting me know jour judg-
-mcnr.

S A L V. What I think of the opinion of Plato, you may gather
from my words and aftions. I have already in the precedent con-
tcrences exprefly declared my felf more than once ^ I will purfue
the latne ftylc in the prefent cafe, which may hereafter ferve you
for an example, thereby the more eafily to gather what aiy opi-»
won IS touching the attainment of knowledg, when a time fliall

Y olFcr

Themothn irn*
prejfed hjthe fro-
jictent isontljhj
right line.

G. G A L I L ^ u s, his Syllfme^

offer upon fome other day : but I would not have Sagreclns of-
fended at this digreffion.

Sagr. I am rather very much pleafed with it, for that Ire-
member ihat when I ftudied Logick,! could never comprehend that
fo much cry'd up and mofi potent demonfiration of Anfiotle.

Salv. Let us go on therefore^ and let Simplic/Hs, tell nie
what that motion is which the ftone maketh that is held faft in the
flit of the fling, when the boy fwings it about to throw it a great
way?

Simp. The motion of the ftone, fo long as it is in the flit,
circular, that is, moveth by the arch of a circle, whofe ftcdfaft
centre is the knitting of theflioulder,and its femi-diameter the arm
and ftick.

Salv. And when the ftone leaveth the fling, what is its mo-
tion > Doth it continue to follow its former circle, or doth it go
by another line ?

Simp. It will continue no longer to fwing round, for then it
would not go farther from the arm of the projicient, whereas
we fee it go a great way off.

Salv. With what motion doth it move then ?

Simp. Give me a little time to think thereof j for I have ne*
ver confidered it before.

Salv. Hark hither, Sagredus this is the Qjtoddam remimfci
in a fub)e£V well underftood. You have paufcd a great while,
Simplicius-

Simp. As far as I can fee, the motion received in going out of
the fling, can be no other than by a right line j nay, it muft ne-
ccffarily be fo, if we fpeak of the pure adventitious impetus, I
was a little puzled to fee it make an arch, but becaufe that arch
bended all the way upwards, and no other way, I conceive that
that incurvation cometh from the gravity of the ftone, which na-
turally dravveth it downwards. The impreffed impetus^ I fay,
without refpefting the natural, is by a right line.

Salv. But by what right line ? Becaufe infinite, and towards
every fide may be produced from the flit of the fling, and from the
point of the ftones feparation from the fling.

Simp. It moveth by that line which goeth dire£Hy from the
motion whigh the ftone made in the fling.

Salv, The motion of the ftone whilft it was in the flit, you
have aftirmed already to be circular^ now circularity oppofcth
direainefs, there not being in the circular line any part that is di-
reft or ftreight.

S I M p. I niean not that the pro)efted motion is direft in re-
fpcft of the whole circle, but in reference to that ultimate point,
where the circnUr motion determincth, I knovv what I would

fay?

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2°K.B. 9,163

Dialog ueI I.

but do not well know how to exprefs my felf.
Salv. And I alfo perceive that you underftand the bufitiefs,
Wthat you have not the proper terms, wherewith to exprefs the
fame. Now thefc I can eafily teach you , teach you, that is, as
to the words, but not as to the truths, which arc things. And that
you may plainly fee that you know the thing 1 ask you, and onely
want language to exprefs it, tell me, when you flioot a bullet out
of a gun, towards what part is it, that its acquired impetus carri-
eth it >

Simp. Its acquired impetus carrieth it in a right line, which
continucth the reflitude of the barrel, that is, which inclincth nci-
dier to the right hand nor to the left, nor upwards nor down-
wards.

Salv. Which in fliort is afmuch as to fay, it maketh no angle
with the line of ftreight motion made by the fling.
Simp. So I would have faid.

Salv. If then the line of the projefts motion be to continue
without making an angle upon the circular line defcribcd by it,
Whilft it v^as with the projicientj and if from this circular motion it
ought to pafs to the right motion, what ought this right line to be ?

Simp. It muft needs be that which toucheth the circle in the
point of fcparation, for that all others, in my opinion, being pro-
longed would interfeft the circumference, and by that means make
fome angle therewith.

Salv. You have argued very well, and (hewn your felf half a
Geometrician. Keep in mind therefore, that your true opinion
is expreft in thefc words, namely, That the projcft acquireth an
impetus of mOving by the Tangent , the arch defcribed by the
motion of the projicient, in the point of the faid pro)eds fepata^-
tion from the projicient.

Simp. 1 underftand you very well, and this U that which I
would fay.

Salv. Of a right line which toucheth a circle, which of its
points is the neareft to the centre of that circle >

Simp. That of the contafl: without doubt : for that is in the
circumference of a circle, and the reft without : and the points of
the circumference are all equidiftant from the centre.

Salv. Therefore a moveable departing from the contad, and
moving by the ftreight Tangent, goeth continually farther and
farther from the contaft , and alfo from the centre of the circle.

Simp. It doth fo doubtlefs.

Salv. Now if you have kept in liiind the propofitions, which
you have told me, lay them together, and tell me what you gadicr
from them.

S I w p. I think I am not fo forgetful, but that I do reaicmbcr

y 2 tbent.

ThefrojeQ^ mo-
ve th bf the Tan'
gent of the ctrcle of
thg motion frece^
dent tn the potnt of
fepnr^tien.

G. G A L I L ^ u s, his Syflcmc^

them. From the things premifed I gather that the pro)e£t fwiftly
fwinged round by the projicient, in its feparating from it, doth re-
tain an impctm of continuing its motion by the right line, which
toucheth the circle defcribed by the motion of the projicient ii^
the point of feparation, by which motion the proje£i goeth con-
tinually receding from the centre of the circle defcribed by the
motion of the pro jicicnt ^ ^

S A L V. You know then by this time the reafon why grave bo'
dies flicking to the rim of a wheele , fwiftly moved, are extrudeJ
and thrown beyond the circumference to yet a farther diftancc
from the centre.

Simp. 1 think I underfiand this very well j but this new knoW-
ledg rather increafeth than leffeneih my incredulity that the Earth
can turn round with fo great velocity, witlibut extruding up into
the sky, Itones, animals, C^r. . .

S A L V. In the fame manner that you have underftood all this?
you fliallj nay you do underftand the reft : and with recollefting
yoitr felfj you may remember the fame without the help of
'$iers : but that we may lofe no time, 1 will help your memorjf
thereihf You do already know of your felf, that the circular mo-
tion of the projicient imprefleth oh the project an impetus of mo-;
jving {*when tht y come to feparate^ by the right Tangent, the
circle of the motion in the point of fcparation, and continuing ^'
long by the fame the motion ever goeth receding farther and far*
thcr from the projicient : and yoy have fa id , that the projcS
would continue to move alon^by that right line, if there were not
t>y its p>!p^pr weight an inclination of 3pfc?nt added unto iCj froU^
which tfie incurvatipn pf the Imc of motion is derived. It feems
moreover ihat^ you knew of yoiir jfeljf*) 'tliat ti^Jls incurvation al-
ways bended towards the centre of the E^rch, for thither do all
grave bodies tend. Now I proceed a little farther,and ask yoUjWhc-
ther the moveable ^fcer its fepjaration, in continuing the right mo-
tion goeth always equally rece<|ing from the centre, or if you willj
from the circumference of that circle, of which the precedent mo*
tion was a part ^ whicb is as ipucli as to fay, Whether a moveable?
tliatforfaking thepoint of a lTangentj and moving along by the
faid Tsmgent, doth equally recede from the point of contafi, anJ
Trom the circumference of the circle .|- , . . .

S I M P, No, Sir : for the Tangent near to tlie point ot contafti
recedetK very Tittle from the circumference, wherewith it keepetB
^ ^«jry narrow angle, but in its going farther and farth^^
^ff\)^^diftance always cncreafcth with a greater proportion,
that in a circle that fliould have ten yards of diameter, a poio^
^fd^^^^g^t that was diftant from the contaft but two palni^?
wouicfbe three or Four times a^s far diftant from the circumfercnc^

Dialogue* 11.

of the circle, as a point that was diftant from the contagion one
f ^lm, andthe point that was diftant half a pahii, I likewife believe
Would fcarfe recede the fourth part of the diftance of the fecond :
that within an inch or two of the eontaft, the feparation of the
Tangent from tl>c circumference is fcarle difcernable.
^^^•A'LVr Sothat thereceffion of the projeft from the cireumfe-
^^'^crfthfe precedent circular motion is very fmall in the begin-

^^^i-M^ Almoft infenfible.

^C'.^Now tell me a little h the projcft, which from the mo-
tfewiof tht projitcient receiveth an impetus of moving along the
Tangent in a right line, and that would keep unto the fame, did
not its own weight depreG it downwards, how long is it after the
ration, ere it begin to decline downwards.
S I M p. r believe that it beginneth prefently , for it not ha-
ving any tWtig to uphold it, it3 proper gravity cannot but ope-
Oi -/^ . --5
\$ A L v.; 86 €hat, if that fame ftone, which being extruded ffoih
Aat wheel turned abouc very faft, had as great a natural pro(>eiii
fion of moving towards the centre of the faid wheel, as it hath 'to
move towards the centre of the Earth, it wouldbe an ealie mat-
ted fork to-retUrn unto the wheel, o^r rather not to depart from it^
in regard that upon the beginirg of the feparation, the reccflion be*
mg io fraall^by reafon of the it^fitme acutenels of the angle of
Oontaft, every v^ry little of inclination that draweth it back to-
wards thie^ cent le of the wheel, would be fufficient to retain it ^^p^
on^tlie rkft orcircurtrfe^rence,^'- ;^^ ' I" ^i^V'"! '

^^'S't wi^P. i^queftion ttot, but that if one fuppofethat whibh nei-
ther is, nor can be, to wit, that the inclination of thofe griVtf bo-
dies was to gO^tbwatd^tlie centre of the wheel , tliey would never
^r^to^be^kttiided or fhaken ofR

S A L V. But 1 neither do,nor need to fuppofe that which Apt ;
^ t will not <leny but that the ftones arc extruded. Yet I fpeak
this by way of fuppofition, to the end that you might grant me
the reft. Now fanc^ to your felf, that the Earth is that great
Whee!, Which moved with fo great velocity is to extrude the ftones.
¥ou could tell me very well even now, that the motion of prd;e-
®ion ought to be by that right line which touchcth the Earth in
point of reparation : and this Tangent, how doth it notably
f*^de from the fupcrficies of the Terreftrial Globe ?

I M^. I believe that in a thoufand yards, it will not recede
from the Earth an inch. , ,

. S A L V. And did you not fay, that the projeft being drawn by
Its own Weight, declineth from the Tangent towards the centre of
^heEarth>

'^'^ Si MP.

4U foon as it is fe-
parated from the
yrojtcient hegtneth
to decltnto

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2°K.B. 9,163

G. GALiLiEus, his Sjfleme.

Sim?. I (jiid fo, and alfo confefle the reft : and do now plainly
underftand that the ftone will not feparatc from the Earth, for
that its receffion in the beginning would be fachj and fo fmall>
that it is a thoufand times exceeded by the inclination which the
ftone hath to move towards the centre of the Earth, which cen-
tre in this cafe is alfo the centre of the wheel. And indeed it muft
be confefled that the ftones, the living creatures, and the other
grave bodies cannot be extruded ^ but here again the lighter thing*
beget in me a new doubt, they having but a very weak propenfion
of defcent towards the centre j fo that there being wanting
them that faculty of withdrawing from the fuperficies, I fee not,
but that they may be extruded j and you know the rule, that ad
dejirHendHm fufficit unnm.

S A V L. We will alfo give you fatisfa&on in this. Tell mc
therefore in the firft place, what you underftand by light matters,
that is, whether you thereby mean things really fo light, as tha
they go upwards, or elfe not abfolutely light, but of fo fmall gra^
vity, that though they defcend downwards, it is but very flowly j
for if you mean the abfolutely light, I will be readier than yottf
felf to admit their extrufion.

Simp. I fpeak of the other fort, fuch as are feathers, wool, cot-
ton, and the like j to lift up which every fmall' force fufficcth-
yet neverthclelTe we fee they reft on the Earth very quietly.

S A L V. This pen, as it Ivith a natural propenfion to dcfccnd to-
wards the fuperficies of the Earth, though it be very fmall yet I
muft tell you that it fufficeth to keep it from mounting upwards •
and this again is not unknown to you your fcl£ j therefore tell mC
if the pen were extruded by the Vertigo of the Earth, by wh»f
line would it move f

Simp. By the tangent in the point of feparation.

S A L v. And when it fliould be to return, and re- unite it felf ttf
the Earth, by what line would it then move ?

Simp. By that which goeth from it to the centre of
Earth.

S A L V. So then here falls under our confideration tvvo moti'
ons 5 one the motion of projefiion, which beginncth from tb^
point of contaft, and proceedeth along the tangent j and the ^
ther the motion of inclination downwards, which beginncth froU*
the projeft it felf, and goeth by the fecant towards the centre^ and

you defire that the projcSion follow, it is necelfary that the
f^^us by the tangent overcome the inclination by the fecant ; is
not fo }

Simp. So u feemeth to me.

S A L V. But what is it that you think neceflary in the moti<>^^
of the proficient, to make that it may prevail over that inclin*'

Dialogue. IL

^lon, from which cnfueth the feparation and elongation of th^
pen from the Earth >

S.I MP. 1 cannot tell.
' Salv. How, do you not know that? The moveable is here
the lame, that is, the fame pen j now how can the fame moveable
itit)eratc and exceed it felf in motion >

^ iM p. I do not fee how it can overconle or yield to it felf in
tootion, unlefle by moving one while fafter, and another whil^
flower. :

Salv. You fee then, that you do know it. If therefore tH^
projeftion of the pen ought to follow, and its motion by the tanr
gent be to overcome its motion by the fecant, what is it ircquifite
taat their velocities fliould be ?

Simp. Jc is rcquifite that the motion by the tangent be greatCf
than that other by the fecant. But wretch that 1 am! Is it not
^nly many thoufand times greater than the defcending motion of
Jte pen, but than that of the ftone > And yet like a fimple felloW
I had fuffered my felf to be perfwaded, that ftones could not he
extruded by the revolution of the Earth. I do therefore revbkd
iny former fentence, and fay, that if the Earth fliouId move,
ftoncs. Elephants, Towers, and whc4e Cities would of neceffity be
toft up into the Air ^ and becaufe that that doth not evene,'! cotr-
cludc that the Earth doth not move. ' I

. Salv. Softly Sx;«|>//«»i-, you go on fofaft, that I begin to 1j6
more afraid for you,than for the pen. Reft a little, and obferve what
lamgoing tofpeap. If for the reteining of the ftone or pen an-
nexed to the Earths iurface it were neceffary that its motion of
ddccnt ^ere greater, or as much as the motion made by the tan-
gent j you would have had reafon to fay, that it ought of nebefflty
to move as fafi, or fafter by the fecant downwards, than by the
Uagcnt Eaftwards : But did not you tell me even ribw, that a
thoufand yards of diftanceby the tangent from thecontaft, do
tenaove hardly an inch from the circumference ? It is not fuffici-
ent therefore that the motion by the tangent, which is the fame
with that of thediurnall Vertigo^ (or ha fty revolution) be fimply
more fwift than the motion by the fecant, which is the fame with
Jhat of the pen in defcending v but it is requifite that the fame be
^ much more fwift as that the time which fufficcth for the pen
move i\g. a thoufand yards by the tangent, be infufBcient for
<o move one fole inch by the fecint. The which I tell you fliall
L^^' though you fliould make that vAOtiM never fo fwift,
^ndthn^cverfo How.

Sim p. And why might not that by the tangent be fo fwift, as
ot to give the pen time to return to the furface of the Earth > .
^ AL V. Try whether you can ftate the cafe in proper termcs,

and

»7T

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2°K.B. 9,163

«yf ^eowetricMl
demoMflration to
prove the impffjjfi-
hilitj of etctTHftoM
hj nteans of the
ttrrefirial v-rrigo.

G. G A L I L it u s , his SjfJeme.

and I will give you an anfwer. Tell me therefore , how much
you think fufficeth to make that motion Ivvifter than this ?

Simp. 1 will fay for example , that if that motion by the tan-
gent w^re a million of times fwifter than this by the fecant , the
pen, yea, and the ftone alfo would come to be extruded.

Salv. You fay fo, and fay that which is falie , onely for
want , not of Logick, Phyficks, or Metaphy ficks , but of Geome-
try 5 for if you did but underftand its firft elements , you wouM
know 5 that from the centre of a circle a right line may be drawn
to meet the tangent , which interfefteth it in fuch a manner , that
the part of the tangent between the contaft and the fecant , may
be one, two, or three millions of times greater than that part o(
the fecant which lieth between the tangent and the circumference)
and that the neerer and neerer the fecant fliall be to the conta&
this proportion (hall grow greater and greater /;/ injinitHm h
that it need not be feared , though ih^ 'vmigo befwift, and the
motion downwards flow , that the pen or other lighter matter can
begin to rife upwards , for that the inclination downwards always
cxcecdeth the velocity of the projefiion.

S A G R. I do not perfcfily apprehend this bufinefl'e.
Salv. I will give you a moft univerfal yet very eafie demon'
ftration thereof. Let a proportion be given between B A \jn Fig-
g.] and C : And let B A be greater than G at pleafure. And le^
there be defcribed a circle , whofe centre is D. From which it
required to draw a fecant , in fuch manner , that the tangent flia/
be in proportion to the faid fecant , asB A toC. Let
fuppofed a third proportional to B A and G. And as B I is
1 A , fp let the diameter F E be to E G and from the point
Jet there be drawn tlte tangent G H. I fay that all this is done a5
was required ^ and as B A is to C , fo is H G to G E. And in rc
gard that as B 1 is to I A 5 fo is F E to E G j therefore by compo'
iition , as B A is to A I j fo fliall F G be to G E. And becaufc C
is the middle proportion between B A and A I *, and G H i^ ^
nuddle term between F G and G E \ therefore , as B A is to C>
fo fliall F G be to G H i that is H G to G E , which was to ^
dcmonftrated.

Sa G R. I apprehend this demonftration ^ yet neverthclefle 5 '
am not left wholly without hacfitation j for I find certain conft'
fed fcruples role to and again in my mind , which like thick an^l
dark clouds , permit me not to difcern the cleernelTe and neceflity
<>f the conclufion with that perfpicuity , which is ufual in Mathe-
matical Demonftrations. And that which I ftick at is this. It
true that the fpaces between the tangent and the circumference
gradually diminifli in injinitHm towards the contafi . but it is al^^
true on the contrary , that the propenfion of the moveable

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2°K.B. 9,163

Dialogue IL
J^fccading growcth Icfi. & Icfs in it, the nearer ic is to the fir ft term
of icsdelccnr ; that ib, to the ftace of reft ; as is manifeft from that
which you declare unto us,dcmonftrating that the deicendmg grave
body departing fiom reft, ought to paife thorow all the degrees of
tardity comprehended between the laid reft , 8^ any aQigned degree
of velocity, the which grow Icis and lels /// infiniium. To which may
be added, that the laid velocity and piopenfion to motion, doth for
another realon diminilTi to infinity \ and it is becaufe the gravity of
the faid moveable may inlinitcly diminiOi. So that the cauies which
diminifhthepropenfion of afcending , and coniequently favour
the projection, aie two;, that is, the levity of the moveable, and its
vicinity tq the ftateof reft, both which are augmen table m infinit.
and thele two on. the contrary being to contract but with one fole
^aufc of making the pro)eaion?l cannot conceive how it alone, al-
though it airo do admit ofinfinitc augmentation, fhould be able to
remain invincible againft the union & confederacy of the others,w^''
arc two, and are in like manner capable of infiiute augmentation.

S A 1, v. This is a doubt worthy oiSagredHS'y and to explain it To as
that we may more cleerly apprehend ic , for that you lay that you
your fclf have but a confufed Idea of it , we will diftinguifh of the
fame by reducing it into figure ; which may alto perhaps aftord us
fome cafe in reiolving the lame. Let us therefore [in f ig.^:] draw
a perpendicular line towards the cent/e,and let it be AC, and to it
at right angles let there be drawn the Horizontal line A B , upon
which the motion of the projeftion ought to be made^ now the prd-
)ca would CQUtinue to move along the fame with an even motion5if
fo be its gravity did nut incline it df» wnwards. Let us fuppofe from
the point ^ a. right line to be drawn , that may make any angle at
plcafure with the line A which let be A E, and upon AB let us
mark fame equal fpacc. AF, FH, HK, and trpm them let us let fall
t^ perpendiculars FG, HI, K as far as AE. And becauie, as al
ready hath been Caid,thedefcending grave body departing from reft,
goeth from time to. time ^cq^iring a greater dpgree ot velocity,
according as the faid time doth fuf celfively encreafe y we may con-
ceive the fpaces Ab\ FH,HK, to reprefent unto us equal times^ and
-the perpendicidars FG> HI, KL, degrees of velocity arcquircd in the
faid times, fo that the degree of velocity acquired uv the av hole time
AK, is as the line K L, in refpea'to. the degree H t ^^f'^'l^^^^
^imc AH,an4 the degree FG in the time AF,the which degrees KL,
Wl>FG,arc(as i. manifeft)the fame in proportion, as the timt s K A,
F a, and if other perpendiculars were drawn from the points
"^rked at pleafure in the line F A , one might iucceflively find de-
gr^es leff, Ld lefle in tnfimtnm , proceeding towards the point A,
rcprefentin^ the firft iijftant of time, and the hrft ft^te of reft. And
^hi« retreat towards A, repre&n(fth the Jirft propeaffon to the

A LI us, hit ^y"em(

motion of defcent , diminifticd in infimtHm by the approach of
the moveable to the firft ftatc of reft, which approximation is
augi^ntable in infinitum. Now let us find the other diminution
of velocity > which likcwife may proceed to infinity , by the di'
minutiW of the gravity of the moveable ? and this (hall be repre-
fented by drawing other lines from the point A , which contein
angles leffe than the angle B A E , which would be this line A Vj
the whicL interfeding the parallels K L, H I, F G , in the point!!
M5 N, iinJO, reprefent Unto us the degrees F O, H N, K M>
acquired in the times A F, AH, A K , leffe than the other de-
grees F G , H I , K L 9 acquired in the fame times but thele
latter by a moveable more ponderous , and thofe other by ^
moveable more light. And it is manifeft , thacby the retreat of
the line E A towards A B , contrafting the angle E A B (j^^
which may be done in infinitum , like as the gravity may in if^fi'
n/fMwbe diminiflied) the velocity of the cadent moveable niay
in like manner be diminiflied in infinitum , and fo confcquently
the caufe that impeded the projeftion i and therefore my thinks
that the union of thefe two reafons againft the projedion , dimi-
niflied to infinity , cannot be any impediment to the faid projc
ftion. And couching the whole argument in its fliorteft terms ,
will fay , that by contrafting the angle E A B , .the degrees of ve-
locity L K, IH, GF, are* diminiflied i and moreover by the re-
treat of the parallels K L, H I, F G , towards the angle A , the
ifame degrees arc again diminiflied ; and both Ihefe diminutions
extend to infinity : Therefore the velocity of the motion of dc'
•fcent may very well diminifli fo much, (it admitting of a twofold
diminution in infinitum^ as that it may not fuffice to reftore
moveable to the circumference of the wheel , and thereupon may
occafion the projedion to be hindered and Wholly obviated.

Again on the contrary , to impede the projeftion , it is necdP
ftrjr that the fpaces by which the proved is to defcend for tl>^
reuniting' it fclf to the Wheel , be made fo ftort and clofe togc"
thcr, that though the defcent of the moveable be retarded ,
morcjdiminiflied in infinitum^ y«t it fufficcth to reconduft it thitM*
and therefore it would be rcquifite, that you find out a dimintit'*
on of the faid fpaces, not only produced to infinity, but to fuch
infinity, as that it may fupcrate the double infinity that is madet^^
the diminution of the velocity of the dcfcending moveable.
how can a magnitude be diminiflied more than another, vvhic»*
^3^th a twofold diminution in infinitum } Now let Simplicitis oh'
fcrvc how hard it is to philofophate well in nature, without 6^^
/^^fry- The degrees of velocity diminiflied in infinttum^ as vccH
•by the dimlntition of the gravity of the moveable, as by the ^p'
proxination to the firft term of the motion, that is, to die ft^^^

DiALOtJUE n.
of reft, are alwayvs determinate, and anfwcr in proportion to the
parallels comprehended between two right lines that concur m
an angle , Uke to the angle B A E, or B A D , or any other
infinitely more acute , alwaycs provided it be rcailmeall.
But the diminution of the Ipaces thorow which the moveable is
to be condufted along; the circumference of the wheel, is propor-
tionate to another kind of diminution, comprehended between
lines that contain an angle infiiiicely more narrow and acute, than
any reSilineal angle, how acute loever, which is that in our pre-
fcntcafe. Let any point b.; taken in the perpendicular AC, and
making it the ce.urc, defcribe at the diftance C A, an arch AMP,
the which (hall interfea the parallels that determine the degrees of
velocity, though they be very minute, and comprehended within
a moft acute reflilineal angle -, of which parallels the parts that
lie between the arch and the tangent A B, are the quantities of
the fpaccs, and of the returns upon the vtfheel, alwiycs leffer (and
with greater proportion leffer, by how much neerer they approach
tothecontaa) than the faid parallels of which they are parts-
The parallels comprehended between the right lines in retiring to-
wards the angle diminifh alwayes at the fame rate as '^.g- AH be-
ing divided in two equal parts in F, the parallel H I fliall be dou-
ble to F G, and fub-dividing F A, in two equal parts, the paral-
lel prq^uced from the point of the divifion (hall be the half ^
F G i and continuing the fub-divifion in infinitHm, the fubfequent
parallels fliall be alwayes half of the next preceding •, but it doth
not fo fall out in the lines intercepted between the tangent and
the circumference of the circle : For if the fame fub-divifion be
made in F A j andfuppofing for example, that the parallel which
Cometh from the poipt (f, were double unto that which commeth
frpm F, this' (hall be marfe then double to the next following, and
continually the neerer we come towards the contaft A, vve Ihall
find the precedent lines contein the next following three, four,
ten, an hundred, a thoufand, an hundred thoufand , an hundred
millions of times, and more in infinitum. The brevity theretorc ot
fuch lines is fo reduced, that it far exceeds what is reqmfite to make
the projea , though never fo light, return, nay more , eontuiuc
unremoveable upon the circumference.

S A G R. i very well comprehend the whole difcourle, and upon
Whatit layeih all its ftreffe, yet nevertheleff. methinks that he
^Hat would take pains to purfue it, might yet ftart ^omcj^nhc,
•l^eftions, by faying, that of thofe two caufes which render the.
if^ntoi the moveable flower and flower in infinnnm ,t ,s mam-
feft, that that which dependeth on the vicinity to the firft term of
the dtfcent, increafeth alwayes in the fame proportion, like as the
paraUels agaves retain the fam; proportion to each other, Sec

1 2 but

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2°K.B. 9,163

i8o

? A L

yUcmc

butthat'thedimi4V^.tioaof the fume velocity, dependent on the
diminution of the gravity ot the moveable (which was the fecono
caule) doth alio obicrve the lame proportion, doth not fo plainly
appear, And who (hall aflare us that it doth not proceed accor-
ding to the proportion of the lines intercepted between the fecant,
and the circumference ] or whether with a greater proportion ?

S A L V. I have affumed for a truth, that the velocities of movea-
bles defcending naturally, will follow the proportion of their gra-
vities, with the favour of Simpltcim, and of Ariflotle, who docH
in many places affirm the fame, as a propolition manifelt : YoU)
in favour of iny adverfary, bring the fame into qucftion, and fay
that itspofiible that the velocity incrcafeth with greater propof'
tion,yea and greater 2/2 infinitum than that of the gravity ^ fo that
all that hath been faid fallcth to the ground : For maintaining
wheregf, 1 fay, that the proportion of the velocities is much leifc
than tfeat of the gravities j and thereby I do not onely fupport
but cc^hfirmc the premifes. And for proof of this 1 appeal unto
experience, which will fhcw us, that a grave body, howbeit thirtt
or foarty times bigger then another j as for example, a ball ot
lead, and another of fugar, will not move much more than twice
as faft. Now if the projeftion would not be made, albeit the ve-
locity of thecadcnt body (hould diminiih according to the pfO-
f ortion of the gravity, much Icffc would it be made fo long as ch^
velocity is but little diminiflied, by abating much from the gravi-
ty. But yet fuppofing that the velocity diminiflieth with a prop<>f''
tion much greater than that wherewith the gravity decreafeth, n^ \
tbougb it were the fclf-fame wherewith thoie parallels conteinc^
between the tangent and circutnferei>ce do decreafe, yet cannot I
fee any neeeflity why 1 (hould grant the projciftion of matters <i
never fo great levity , yea I farther averrc, that there could no fw^h
projedion follow, meanirrg al way es of matters not properly an^
abfolutely light, that is, void of all gravity, and that of their
'natures move upwitrds , but that defcend very flowly, afi|J
^have very ftnall gravity. And that which moveth me fo to thi^
IS, tha'tthe diminution of gravity, made according to the prop<^'
Hiitfh of the parallels between the tangent and the circumference'
hath for its ultimate and highcft term the nullity of weight, as thofr
parallels have for their laft term of their diminution the contaft
felf, vvhich is an indivifible point ; I^ow gravity never diminifh^^'*
fofar ^s to its laft term, for then the moveable would ceafe to b^
g'-avc •, but yet the fpace df the reverfion of the pro;e£i to tb^
circmtiference is reduced to the ultimate minuity, which is wh^
'Vhe itroN/^able refteth upon the circumference in the very point *
eoritaft h fo as that to return thither it hath no need of fpac^ '
and therefore let the propenfion to the motion of dcfcent be ti^'

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2°K.B. 9,163

Dialogue.

l8t

vtr io Imall, yet is it alwaycs more than fufficient to reconduft the
moveable to the circumference, from which it isdiftant but its leaft
fpace, that is, nothing at all.

Sagr. Your ditcourfe, I muft confefs, is very accurate i and
yet no kfs concluding than it is ingenuous j and it muft be gran-
ted that to go about to handle natural queftions, without Geome-
try y is to attempt an impoflibility.

5 A L V. But Simplicius will not fay fo j and yet 1 do not think
that he is one of thok Feripateticks that diffwade their Difciples
from ftudying the Mtf^fce^itfJic^Jr as Sciences that vitiate the rea-
fon, and repder it leffe apt for contemplation.

Simp. 1 would not do fo much wrong to Plato ^ but yet I may
truly fay with AriBotle, that he too much loft himfelf in, and too
nwich doted upon that his Geometry : for that in conclufion thefc
Mathematical fubtilties S aim at us are true in abftraft, but applied
tofenfible and Phyfical matter, they hold not good. For the
Mathematicians will very well demonftrate for example, that
Sph^ra tangit planum inpnn^o j a pofition like to that in difpute,
but when one Cometh to the matter, things fuccced quite another
way. And fo I may fay of thefe angles of contad, and thefe
proportions ; which all evaporate into Air, when they are applied
to things material and fcnfible.

6 A L V. You do not chmk then, that the tangent touchedi the
fuperficies of the terreftrial Globe in one point only ?

8 I M p. No, not in one fole paint ^ but I believe that a right
^gopthmany teas and hundreds of yards touching the furface
^otx>ndy jrf the Earth, but of the water, before it feparate from
<iiefame. . I

S A L V. But if I grant you this, do not you perceive that k «ia*
ieth fo aiiMQh cbc more agiinft your caufe ? For if ic be fuppofed
the tangent was feparatedfitjm . the terreftrial fuperficies, yet
^'hathbecn however demonftrated that by rcafon of the great a-
<^ity of the angle >of c^ntingence \\i happily it may be call d an
^le> the projca^^ould not fepariate from the fame i how much
leffe caufe of reparation would it have, if that angle fliould be
ijvliolly clofed, and the fuperficies and the tangent become all one ?
Perceive you not that the Pro)eaion would do the fame thing ap-

the furface of the Earth, which is afinuch as to fay, it would firenph bj con^
do )uft nothing at all? You fee then the power of troth, which
IL, i ^hile you ftrive to oppofe it, your own affanlts thcmfelves uphold

The trnth
fomitimet gaines

^«iie you ftrive to oppole it, your own aiiauu^

defend it. But in regard that you have rctrafted this errour,
^'Wouldbe loth to leave you in that other which you hold, namely,
rAat a material Sphere doth not touch a plain in one fole point :
'^ndlcould^vifh fomeifew hours converfation with fome perfons
^avecfant^in Gcawerrv, might make you a little more intelligent

amongft

The If hen al-
though material-,
toucheth the mate-
r^l platie hut in
9pe^int onely.

The definition of
the fpbtre.

i§i G. Galileos, Syjleme,

aiTiongft thofe who know nothing thereof. Now to fliew you how
great their errour is who fay, that a Sphere <v,g, of braffe, doth not
touch a plain if.g* of fteel in one folc point , Tell me what con-
ceipt you would entertain of one that fliould conftantly avcr^ that
the Sphere is not truly a Sphere.

Simp. I would eftcem him wholly devoid of rcafon.
S A L V. He is in the fame cafe who faith that the material Sphere
doth not touch a plain, alfo material, in one onely point , for to
fay this is the fame, as to affirm that the Sphere is not a Sphere*
And that this is true, tell me in what it is that you conftitute the
Sphere to confift, that is, what it is that maketh the Sphere differ
from all other folid bodies.

S I M p. 1 believe that theeffenceof a Sphere confifteth in ha-
ving all the right lines produced from its centre to the circumfe-
rence, equal.

S A L V. So that, if thofe lines fliould not be equal, there fame
folidity would be no longer a fphere ?
Simp. True.

S A L V. Co to 5 tell me whether you believe that amongft the
many lines that may be drawn between two points, that may be
more than one right I'me onely.
Simp. There can be but one.

S A L V. But yet you underftand that this onely right line Ihall
again of ncccffity be the (horteft of them all ?

S I M p. 1 know it, and alfo have a demonftration thereof, pro-
duced by a great Ferip/r/^^rf^Philofopher, and as I take it, 'if my
memory do not deceive me, he aUcdgeth it by way of reprehending
Archimedes^ that fuppofeth it as known, when it may be demon-
ftrated. /i ; ii -.^ .

: S A L V. This muft needs be a great Mathematician, that knew
how to demonftrate that which Archimedes neither did, nor coulcl
demonftraite.; > And if you rerhember his demonftration, I woul^
gladly hear'it : for I remember very well, that Archimedes in
Books,<ie Sphixra ,(^ Cylindro^ placeth this Propofition amongft th^
Pojiulat^ h and 1 verily^ believe that he thought it demonftrated.

SiMF. I think I (hall remember it, for it is very eafie
Ihort.

; Sal v. The difgrace of Archimedes, and the honour of this PJ^'j
lofopher ftiall be fo much the greater.

Simp. 1 will defcribe the Figure of it. Between the poio^^
.r^cpersp^rc- ^ ^^g 5'] ^raw the right line A B, and the curve X^^^

Ikktta f^roveth^ A C B, of which we wiH prove the right to be the fliorter : an^»
ro he th^ the proof is this i take a point in the curve- line, which let be
^ and draw two other lines, A C and C B, which two lines together,
are longer than the folc line A B, for fo demonftrateth EncU^'

The dfmonjlrar

righ line
fhortefiofad

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2°K.B. 9,163

Dialogue. IL

But the curve-rine A C B, is greater than the two right-lines A C>
.*nd C B j therefore, a fortiori^ the curve-line A C B, is much
greater than the right line A B, which was to be demonftfated.

Salv. 1 do not think that if one ftould ranfack all the Para-
. logifms of the world, there could be found one more commodious
ilian this, to give an example of the moft folemn fallacy of all
fallacies, namely, than that which proveth ignotnm per tgnotim.

Simp. How fo? •

Salv. Do you ask me how fo ? The unknown conclufion
which you defire to prove, is it not, that the curved line A C B, is
longer than the right line A B i the middle term which is taken
for known, is that the curve-line ACB, is greater than, the two
lines A C and C B, the which are known to be greater than A B;
And if it be unknown whether the curve-line be greater than the
fingle right-hne A B, fliall it not be much more unknown whether

be greater than the two right lines A C & C B,which arc known
to be greater than the fole line A B, & yet you affume it as kilown.^

Simp. I do not yet very well perceive wherein lyeth the faU

S A. L V. As the two right lines are greater than A B, (as may be
Kppwn by Euclid) and in as much as the curve line is longer than
ihe two light lines A C and B C> fliall it not not be much greater
^han the iole right line A B ?

Simp. It fliall fo.

S A L v. That the curve-line ACB, is greater than the right
line A b the conclufion mote known than the middle term,
V^hich is, ;hat the fame curve-line is greater than the two right-
Ijjiet A C'^jid C • Now when the middle term is lefs known
Wn ^Jic conclufion, it is callqd a proving ignotum per ignotiut.
rf^^ tp rctiji^p to ourpurpofe, it is fuflScient that you know the
]i^c to h^e the (hortVft of all the lines that can be drawn be-
^Vvccn two( points. And ?s to the principal conclufion, you (ay,
d)a? t|)e majtierial fphere doth not touch the fpherc in^ one folc
poipg. ; Wh^t then is its contaS >

Simp. It fliall be a p irt of its fuperficies.
- Sal v. And the cpntaft likcvj^ife of another fphere-equ^l to the
%ft, fliall bf alfo a Hke particle of its fuperficies ?

Simp. There is no reafoa vvhy it ftiould be othervvife.

Salv. Then the two fpheres which touch each other, fliall
yvith the two fame particles of a fuperficies^for each of them
??^!^j^ing to one and the fame plane, they muft of neeeffity agree
p p. 'tanner to each other. Imagine now that the two fpheres

A^^'^'^ whofe centres are AandB, do touch one another:
^fc t ^^^^^ centres be con;oyned by the right line A B, which
g^fleth through the contaft. It paiTcth thorow the point C, an<|

another

•f the fame PeripM
tetickj^ which fro
vetb onoLUtn pc
ignociiks.

that the jphtre ton-
cheth the ft^nt but
in o»i feint*

Why the fphere in
aBjfrM^^ toucheth
the plane -cnely tn
one point, And not
the m^teriMl in
concrete.

G. G*A L I L ^ u s , Im SjlJeme.
snjDjhcr point in the contaft being taken as O5 conjoyn the two
light lines A D and B D, lb as that they make the triangle A D
of which tlie two (ides A D and D B fliall be equal to the other one
A C B, both thole and this containing two leniidiameterS) wlrjch
by the definition of the fphere are all equal : and thus the right
line A B, drawn between the two centres A and B, (hall not be the
fliorteft of all, the two lines A D and D B being equal to it: which
by your own conceflion is ablurd.

Simp. This demonftration holdeth in the abftiaSed, but not in
the material fpheres.

Salv. Inftance then wherein the fallacy of my argument con-
fiftcth, if as you fay it is not concluding in the material fpheres, but
holdeth good in the immaterial and abftrafled.

Simp. The material fpheres are fubjeft to many accidcntSj
which the immaterial are free from. And becaufe it cannot be,
that a fphere of metal pafling along a. plane, its own weight ftoul<J
notfo deprefs it, as that the plain ftiould yield fomcwhat, or that
the fphercit ielf fhould not in the contaft admit of Ibme imprelfi'
on. Moreover, it is very hard for that plane to be perfeft, if for
nothing elfe, yet ar leaft for that its matter is porous ; and per'
haps it will be no lefs difficult to find a fphere lo perfeft , a^ tba^
it hath all the lines from the centre to the fuperficies, cxaftJy
equal.

Salv. I very readily grant you all this that you have faid i but
itis vecy much befide our purpofe : for whilft you go about to
{hew me that a material fphere toucheth not a material plane
one poiat aloncy you make ufe of a fphere that is not a fphere, an^l
of a plane that is not a plane 5 for that, according to what yo^
fay, either tl^fc things cannot be found in the world, 01 if they
may be fbund, they are fpoiled in applying 'them to workthe eftcft
k faad been therefore a lefs evi^, for you to have granted the co/i''^
clufion, but conditionally, to wit, that if there could be made of
matter a fphere and a plane that were and could continue perfcft
they would touch in one fole point, and then to have denied th^
any fuch could be made. : .

S I . J believe that the propofition of Philofopliers is to
underftood in this fenfe j for it is not to be doubted, but that the
,impcrfeflion of thd rtiattcr , maketh the matters taken in coti'
Crete, to dilagrce with thofe taken in abftraft.
i SAiL>Y. What, do they not agree .> Why, that which yoUV^^^^
fclf fay at this inftant, proveth that they punftually agree.
Simp, How can that be .>

Salv. Do you not fay, that through the imperfection of th^
matter,:thatbody vvh!ch oughttobe perfcftly fpherical, and th^^
plaup \Vhicb Qught to be perfeftly level , do not prove to be th^

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2°K.B. 9,163

DiALOGtlE. iL ^'

^amc in concrete, as they are imagined to be in abftraft ?
• S i M p. This I do affirm.
^ALV.Then whenever in concrete you do apply a material Sphere
a niatetial plane, yoiiapply an nnperieCt Sphere to an imperiect ^niy the f*me in
P'ane, &: thele you lay do not touch only in one point. But I mufl: ^
^cU you, that even in abftiacTt an immaterial Sphere, that is^ not a
perfeft Sphere, may touch an immaterial plane, that is, not a per-
^^ft plane, liot in one point, but with part of its fupcrficicsjlb that
hitherto that) which falleth out in concrete, doth in like manner
hold true inabftra^i-. And it would be a new thing that the com-
putations and rates made in abftraS number!!^, fliould not after-
wards anfwer to the Coines of Gold and Silver , and to themer-
chaadizci in concrete. But do yoii know S'mplicim^ ho.w this
comnieth to paffe ? Like as to make that the computations agree
^'ith the Sugars, the Silks, the Wools, it is neceffary that the
^ccomprant reckon his tares of chefts, b^gs, and fuch other things:
J^o^ when the Geometncall P hiiojopher would obferve in concrete
^he effe&s demonftrated in.abftradi:, he muft dcfalke the impedi-
«ientsof the matter, and if he know how to do that, I do afliire
y^^u, the things fliall jump no leffe exaftly , thaji Arithmetical
•Computations. The crroiirs therefore lycth neither in abftraft, nor
>n concrete, nor in Geometry ^no^'inPhyftckjy but in the Calcula-
tor, that knowcth not how to adjuft hb accompts. Therefore if
you had a pcrfeft Sphere and plane, though they were material,
you need not doubt but that they would touch onely in one point.
Af>d iffucha Sphere wasand is impdfllble to be procured, it was
"^uch betides the purpofe to fay, ^p/^^r^ dsneanon tangitin
p^n^o, Furthermore, if I grant you SimpliciuS', that in matter a
gure cannot be procured that is perfeftly fpherical, or perfeftly
eve] : 13 Q y^ij think there may be had two materiall bodies,
y.holc luper£cies in fome parr, and in fome fort are incurvated as
'^fegularly as can be defired >

Si M p. Of thcfc I believe that there is no want.

S A Lv. If fuch there be, then they alfo vvill touch in one folc Centra in a fin^
point ^ for this contaft in but one point alone is not the fole and s^^e^int pe-
peculiar pi iviledge of the perfeft Sphere and perfea plane. Nay, he fr^^r™^^^^^
that fhould profecute this point with more fubtil contemplations yutbehngcthtoaii
Would finde that it is much harder to procure two bodies that '^«7'^A«'^«-

IfliirK 'L r % • • t • It u more a'Jp-

Jl'ULnwith partot their inperficies, than with one point onely. cult to find Ftgnres
»f twofuperficies be required to combine well together, it is ^^^^^""'^^ ^'f^*
Ton^^'^ ^^ther, that they be both exaftly plane, or t^at if one be ]\V/th.ZJZ
th"^^^' other be concave^ but in fuch a manner concave, MP'""^-
th^^ W f ^"^^^'^^^^y do exaftly anfwer to the convexity of the other:
^^e which conditions are much harder to be found, in regard of
leir too narrow determination, than thofe others, which in their
^luall latitude are infinite. A a S,mf.

i86

G. G

A L I L i^EU S

erne.

7 be Suberic All
figure is edfur to
be made than gnj
ether*

The circuUr Ft-
jrure cmly u fUced
gmou^ft the poftu-
Uca of AiMthemg.
ticiAMS,

* Demands or
petitions.

S I M p. You believe then, that two ftones, or two pieces of ^
ron taken at chance, and put together^ dofji the moft part touch
in one fole point ?

S A L V. In cafual encounters, I do not think they do i as well
bccaufe for the moft part there will be Ibme fmall yielding filth
upon them , as becaule that no diligence is ufed in applying theiw
without ftriking one another ^ and every fmall matter fufficeth
make the one fuperficies yield fomewhat to the other j fo that
they interchangeably, at leaft in fome fmall particle, receive figure
from the imprcflion of each other. But in cafe their fuperficifS
were very terfe and polite, and that they were both laid upon ^
table, that fo one might not prcffe upon the other, and gently pi*'
towards one another, I queftion not , but that they might be
brought to the fimple contaft in one onely point.

S A G R. It is requifite, with your permiflion, that I propound a
certain fcruple of mine, which c^me into my minde, whirft I heard
propofed by Simplicity the impoflibility of finding a materiaJl
ard folid body, that is, perfcftly of a Spherical figure, and whil'ft
liiw SalviatHS in a certain manner, not gainfaying, to give his
confeiit thereto j therefore 1 \vould know, whether there woul''
be the fame difficulty in forming a folid of fome other figure, that
is, to expreffe my felf better, whether there is more difficulty i^^
reducing a piece of Marble^ jfUp the figure of a perfeft Sphere, than
into a perfea Pyramid, oriq^o 4 pcrfcd Horfe, or into a perfcd
Graffe-hopper ? v

S A L V. To this I will makp you the firft anfwcr ; and in tb^
firft place, I will acquit my felf of the affent which you think ^
gave to Simplicirfs^ which was only for 4 time j for I had it alfo
my thoughts, before I intended to enter upon any other matter,
fpeak that, which,it may be,is the fame 5, or very like to that which
yoq arc about to fay j And anfwering to your firft queftion, I fay»
that if any figure can be given to a Solid, the Spherical is the cafi'
eft of all others, as it is likewife the moft fimple, and holdeth the
fame place amongft folid figure^, as the Circle holdeth among^
the fuperficial. The defcription qf which Circle, as being more
fie than all the reft, hath alone been judged by Mathematician^
worthy to be put amongft the ^ pojinlata belonging to the defcri'' ,
ption of all other figures. And the formation of the Sphere
to very eafie, that if in a plain plate of hard metal you take aD
empty or hollow circle, within which any Solid goeth cafually
volving that was before but gi oily rounded, itftiall, without an/
other artifice be reduced to a Spherical figure, as perfedi: a? is p^^"
fible for it to be i provided, that that! ame Solid be not lefTe th^^
^he Sphere that woujd pafife thorow that Circle. And that which
yet more wprthy ojf our confideration is, that within the felf-fai^^^

incavity

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2°K.B. 9,163

Dialogue. II.

incavity one may form Spheres of feveral magnitudes. But wLi^
iJ* required to the making of an Horle, or «^as you fay) of a Grai v
hopper, 1 leave to you to judge, who know that there are but ftw
ftatuarics in the world able to undertake fuch a piece ot work.
And I think that herein Sinipliciiis will not dilfent from me.

Simp. 1 know not whether Idoat all diffent from you my
opinion is this, that none c f the afore-named figures can be per-
fcaiy otteined ; but for the approaching as neer as is poflible to
the moft perfcft degree, 1 believe that it is incomparably more ea-
fie to reduce the Solid into a Spherical figure, than into the fliape
of an Horfc, or GrafTe-hopper ?

Sagr. And this greater difficulty , wherein think you doth it
depend >

S i M P. Like as the great facility in forming the Sphere arifeth
from its abfolute fimplicity and uniformgy ib the great irregu-
larity rendereth the conftruflion of all other figuies difficult.

S A G R. Therefore the irregularity being the caufc of the diffi-
culty^ than the figure of a ftone broken with an hammer by
chance, lhall be one of the figures that are difficult to be introdu-
ced, it being perhaps more irregular than that of the horfe >
Simp. So it fliould be.

S A G R. But tell me that figure what ever it is which the ftone
hath, hath it the fame in perfeftion, or no >

Simp. What it hath, it hath fo perfeftly , that nothing can be
inore exaft.

S A G R. Then, if of figures that arc irregular, and confequent-
Jy hard to be procured, there are yet infinite which are moft per-
fcftly obteined , with what reafon can it be faid, that the moft
fiinple, and conlcquently the moft eafie of all, isimpoffible to be
Focured;^

S A L V. Gentlemen, with your favour, I may fay that vve have
rallied out into a difputc not much more worth than the wool of a
goat j and whereas our argumentations ftiould continually be con-
Vcrfant about ferious and weighty points, we coniume our time in
frivolous and impertinent wranglings. Let us call to minde, I pray
you, that the learch of the worlds conftitution, is one of the grea-
teft and nobleft Problems that are in nature ; and fo much the'
greater, inaimuch as it is direfted to the refolving of that other ^
to wit, of the caufe of the Seas ebbing and flowing, enquued in-
by all the famous men, that have hitherto been in the world,
pofllbly found out by none of them. Therefore if we have
^^^^i»g more remaining for the full confutation of the argument
taken from the Earths -jertigo, which was the laft, alledged to
prove its immobility upon its own centre, let us paffe to the ex-
amination of thofe things that are alledged for, and againft the
^finual Motion, A a 2 S a g

IrreguUr fornti
difficult to be tK'
t reduced.

The eonfiitHtion
of the Vniverfe is
one of the moftnO'
ble Problem.

G. G A L I L ^ u his Syjlcme.

S A G R. I would not have yoUy Salvi at j^s-, mcafure our wits by
thelcalcof yours : you, who ufe to be continually bufied about
the iublinieft contemplations, cftccm thofe notions frivolous and
below you, which we think matters worthy of our profoundcft
thoughts : yet fometimes for our fatisfaciion do not difdain to
ftoop folow asto give way a little to our curiofity. As to the
refutation of the laft argument? taken from the cxtrufions of the
diiirnal ^eriigo^ far lefs than what hath been laid, would have
given me fatisfa&on : and yet the things fuperfluoufly fpokeH)
feemcd to mc fo ingenious, that they have bcca fo far from wea*
rying my fancy, as that they have, by reafon of their novelty, efl*
tertained me all along with fo great delight, that 1 know not hoW
to defire greater : Therefore, if you have any other fpeculation
to add, produce it, for I, as to my own particular, fliall gladly
hearken to it. ^

S A L V. 1 have always taken great delight in thofe things which
I have had the fortune to difcpver, and' next to that, which is my
chief content, I find great plcafure in imparting them to foiue
friends, that apprehendeth and feemeth to like them : Now, in re-
gard you are one of thefe, flacking a little the reins of my ambi-
tion, which is much pleafed when 1 fliew my fe]f more perfpi-
cacip\is , than fome otJier that hath the reputation of a fliarp
fight, I will for a full and true meafure of the paft difpute, prO'
duce aiipt^icr fallacy of the, Senators of Ftolomey and ArijiotUi
which I fake from the argument alledged.
S.A j^,^v. See how greedily 1 wait to hear it.
j S A,i-Y^, We have hitherto over-palTed, and granted to Ptolomp
a^k aA cJ^air^^ of the done proceed'.

\ng j^p^^ithc velocity of the whjeeV turn d round upon its centre?,
the caufe of the faid extruilon encreafeth in proportion, as the ve-
locity o^ the vertigo (or whirling J is augmented ; ftom whenc^
it JW^ap^ ^pjferrc^d |, ;that the velocity of the Earth's vertigo being
.vey/;ai^cj^ greater; than that of any machin whatfoever, that
caa^ke.jiP turn tound artificially ^ the extrulion of iiones, oi
i ii-B^Is&^if. would confequehtly be far more viole^^t^., NoWi,l

; wr v^/th»^ f 1^^ is a great fallacy in this difcourfe, in that we
com J>are thcfe velocities indifferently and abfolutcly to one ^ti^"
ther. J ItV true, that if I comparethc velocities of tlie fame wheel)
or of , tvvo wheels equal to each other, that which jfhall be m^^^
fvyiftly turn d round , fliall extrude the lione with greater vit>'
lence • and the velpcity encreafing, the caufe of the projefii^^^
AaiL\i\^ewife encre^fe : but when the velocity is augmented, tiO^
cpciteafingi the velocity in the fame wheel, which would be by
piuCpg it to maK c ; (greater number of revolutions in equal tinie^ j
"^^^if^j^^"' diameter, and making the wheel greater, 1^

' ^^'PS"P the fame time in the leffer whccJ?

Dialogue, 11.

as in the greater, the velocity is greater bnely in the bigger wheel, ^^.J/^jV^l^f^^^^^
for that its circumference is bigger , there is no man that thinketh eth not accor<i^"g^

^ ' " ' t9thi praportio** of

the velocity ,
Creafed by ntaki»r
the rvheel hi^^er.

that the caui'e of the cxtrufion in the great wheel will cncreafe ac
cording to the proportion of the velocity of its circumference) to
Ae velocity of the circumference of the other lefler wheel., for that
this is moll: faU'c, as by a moft expeditious experiment I (hall thus
grofly declare : We may fling a ftone with a flick of a yard long,
farther than we can do with a ftick fix yards long, though
the motion of the end of the long ftick, that is of the ftone placed
in the flit thereof, were more than double as fwift as the mo»
tion of the end of the other fliortcr ftick , as it would be if
the velocities were fuch that the leflTer ftick fliould turn thrice
round in the time whilft the greater is making one onely con-
verfion.

S A G R. This which you tell me, Salviatm-, niuft, I fee, needs
fucceed in this veJ-y manner ^ but I do not fo readily apprehend
the caufe why equal velocities ihould not operate equally in
extruding projecl:s, but thac of the Icffer wheel much more than
the other of the greater wheel h therefore 1 mtrcat you to tell me
how this Cometh to pafs?

S I M p. Herein, Sagredm^ you feem to differ much from your
felf, for that you were wont to penetrate all things in an inftant,
^ now you have overlooked a fallacy couched in the experiment
pf the ftick, which I my felf have been able to difcover : and this
is the different mam>er of operating, in making the projeSion one
while with the fliort fling and another while with the long one ,
for if you will have the ftone fly out of the flit, you need not con-
tinue its motion unifomily, but at fuch time as it is at the fwifteft,
you are to ftay your arm, and ftop the velocity of the ftick- where-
Upoti the ftone which was in its fwifteft motion, flycth out, and
^ovcrh with impetuofity : but npw that i>op cannot be made in
the great ftick, which By rcafon of its length and flexibility, doth
^ot entirely obey the check of the arm, but continueth to accom-
pany the ftone for fome fpace, and holdeth if in with fo much lefs
fouce, and not as if you had with a ftiff fling fent it going with a
jerk : for if both the fticks or flings fliould be check'd by one and
the fame obftaclc, I do believe they would fly afwell out of the
one, as out of the other, howbeit their motions were equally
fwift.

S A G R. With the permiflTiou of Sal^iatHS, I will anfwer fome-
^^i^g to Simplichis, in regard he hath addreffed himfelf to me \
I f^y ^ jj^^^ iJj^.g jifcourfe there is fomewhat good
and lomevvhat bad : eood , becaufe it is almoft all

true

bad, becaufc it doth not agree with our cafe : Truth is, that when
tliat which carrieth the ftones with velocity,

flball meet with *v
check

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2°K.B. 9,163

(jrar,' i -g the di ■
urnal vertigo »/
the Earthy ^ that
by [ome ftidden flop
orobjhacle it were
arrefied , heitfes ,
ntOHtttains them'
felves^ and perhaps
the yphcle Globe
rvouldhe jhaken n
piecesi

G, G A L I L i^: u s, his Syflrmc-

check that h immoveable, tliey (hall fly out with great impctuo-
fity : the fame effeft following in that cafe, which we fecdayly
to fall out in a boat that running a twifc courfe, runs a-ground, or
meets with fome fudden ftop, tor all thofe in the boar, being Tur-
prized, ftumble forwards, and fall towards the part whither the
boat ftcered. And in cafe the Earth fliould meet with fuch
check, as fliould be able to refill: and arrcfl its ^crrigo^ then indec
I do believe that not onely beafts, buildings and cities, but moun-
tains, lakes and feas would overturn, and the globe it felf woulJ
go near to fliake in pieces j but nothing of all this concerns our
prcfent purpofe, for we fpeak of what may follow to the motion
of the Earth, it being turn d round uniformly, and quietly about
its own centre , howbeit with a great velocity. That likewife
which you fay of the flings, is true in part •, but was not allcdged
by Sal<z/iatusy as a thing that punftually agreed with the matter
whereof we treat, but onely, as an example, for fo in grofs it may
prompt us in the more accurate confideration of that point, wh
thcr , the velocity increafing at any rate, the caufe of the pro)
&'io[\ doth increafe at the fame rate : fo that z', g. if a wheel
ten yards diameter, moving in fqch a manner that a point of
circumference will pafs an hundred yards in a minute of an hou
and fo hath an impetus able to extrude a ftone, that fame impet
ftiall be increafed an hundred thoufand times in a wheel of a millio
of yards diameter, the which Sal*viatus denicih, and I incline to h*
opinion ^ but not knowing the reafon thereof, I have requefted i
of him, and ftand impatiently expefting it.

S A L V. I am ready to give you the beft fatisfaftion , that m
abilities will give leave : And though in my firft difcourfey'
thought that 1 had enquired into things eftranged from our puf
pofe , yet never thelcffe I believe that in the fequel of the difput^
you will find that they do not prove fo. Therefore let Sagred
tell me wherein he hath obferved that the refinance of any mov
able to motion doth confift.

S A G R. I fee not for the prefent that the moveable hath any
internal refiftance to motion , unlcfTe it be its natural inclination
and propenfion to the contrary motion , as in grave bodies , that
havea propenfion to the motion downwards, the refiftance is
the motion upwards , and I faid an internal refiftance', becauC^
of this, I think, it is you intend to fpeak , and not of the extern
refiftances , which are many and accidental.

S A L V. It is that indeed I mean , and your nimbleneflfe of wit
hath been too hard for my craftinefTe , but if I have been too
fliort m asking the queftion , I doubt whether Sagredus hath been
full enough in his anfwer to fatisfie the demand , and whether
there be not in the moveable, befides the natural inclination to the

contrary

Dialogue II.

contrary term , another in trinllck and natural quality , which nna-
I^eth it aver fe to motion. Therefore tell me again ^ do you not
^hink that the inclination *v, of grave bodies to move down-
^vards, is equal to the reliftancc of the fame to the motion of pro-
jeSion upwards ?

S A G R. 1 believe that it is cxa&ly the fame. And for this reafon
I fee that two equal weights being put into a ba 1 lance , they do
ftand ftillin cqnilihrinm , the gravity of the one refifting its be-
ing raifed by the gravity wherewirh the other prefling down-
wards would raifc it.

S A L V. Very well ^ fo that if you would have one raife up the
other, youmuft encreate the weight of that which dcpreffeth,
or leffen the weight of the other. But if the rcfiftance to afcend^
niotion cunfift onely in gravity , how cometh it to paffc ? that

hallances of unequal arms , to wit in the * S/i/i^r// , a weight
Sometimes of an hundred pounds , with its preflion downwards,
^oth not luffice to raife up on of four pounds ^ that (hall counter*
PPife with it , nay this of four , defccndipg fliall raife up that
an hundred; for fuch is the efFea of the pendant weight upon
^he weight which we would weigh ? If the rcfiftance to motion
vefidcth oncly in the gravity , how can the arm with its weight of
four pounds onely > relift the weight of a fack of wool, or bale of
filk 5 which (hall be eight hundred , or a thoufand weight j yea
more, how can it overcome the fack vvith'its moment , and raife
it up ? It muft therefore be confeft Sagredus , that here itmaketh
ufe of fome other rcfiftance , and other force , befides that of
fimplc gravity.

^AGR. It muft needs be f o^ therefore tell me what this fe-
cond virtue fliould be.

S A L V. It is that vvhich was not in the ballance of equal
Wms 'y you fee then what variety there is in the Stiliard ^ and up-
^^thisdoubtlelTe dependeihthe caufe of theneweffea.

S A G R. I think that your putting me to it a fecond time, hath
^adc me remember fomething that may be to the purpofe. In
^oth thcfe beams the bufinefs is done by the weight, and by the
inotion \ ia the ballance, the motions are equal, and therefore the
one weight muft exceed it in gravity before it can move it j in the
*«liard, the lefler weight will not move the greater, unlefs when
ws latter moveth little, as being bung at a leffer diftancc, and the
^^l^er much, as hanging at a greater diftance from the lacquet or
^^^^^ It is nccelTary therefore to conclude, that the leffer weight
ovcrconaeth the rcfiftance of the greater, by moving much, whilft
• is moved but little.

^ ^ I- V. Which is as much as to fay, that the velocity of the
^ovcable lefs grave, compenfateth the gravity of the moveable
Siorc grave and lefs fwift. Sag r-

The inclination of
grave heAies to the
moti&n doWHwardfy
u ecjnal to their
re fi fiance to tht
mottoH Howards,

* A porcablc bal-
lance wherewith
market- people
v^reigh their corn-
mod iries, giving ic
gravity by remo-
ving the weigh:
farther from the
cock : call*d by the
Latines, ['ampan/t
trntitta*

The greater vtfv

fcnjates thf^v^oftef.'
gravity .

G. G At I us, his

Sag Rv But do you think that the velochy doth fill ly make
good the gravity ? that is, that the monicnc and force of a move-
able of /z/.^. four pounds weight, is as great as that of one of aif^
hundred weight, whenfoever that the h, ft hath an hyindred degreeJ
of velocity, and the later but four onely >

^ S A L V. Yes doubtlefs, as I aan able by many experiments t
depionfl:rat€ : but for the prefcnt, let this . onely of the ftiliarO*
fiifficc i.fiQ, which you fee that the light end of the beam, is then
able to fuftain and equilibrate the great Woo! fack, wheo.irs di^*
ftanccfrom the centre, upon which the ftiliard refteth and tiirn'^
cth, fhaH jSp much exceed the lefibr diliance, by how much the ab-
folutc gravity of the Wool-fack exceedeth that of th^^pendent
weight. . And we lee nothing that can caufe this inrufticiencie in
the great fack of Wool, to raile with its weight tlie pendent
weight lo much leis grave, lave the dilparity. of the morions which
the one and the other fliould make, whilft thac the Wool fack.by
defcending but one inch onely, will raife the pendent weight an
hundred inches : Cluppofing that the fack did weigh an hifndre4^
times as much, and that the diftance of the Imall weight from thd»
centre of the beam were an hundred times greater, than the di-
ftance between the faid centre and the point of the fc^cks l ufpenfi
on.) . And again, the pendent weight its moving the fpace of a
hundred inches, in the time that the fack movcth but one inc-
onely, is ;the fame as to fay, that the velocity of the motion of tlu
little pendent weight, is an hundred times greater than the veld
city of the motion of the fack. . Now fix it in your belief as
true and manifeft axiom, that the refiftance which proccedeth froi
the velocity of motion, compenfateih that which dependeth oi
the gravity of another moveable : So rhaicunfequently, a move^
able oh one. pound, that moveth with an hundred decrees of ve-
locity, doth asmijch refift all obftrudtion, as another moveabl
of an hundred weight, whofe velocity is but one degree onely^
And two equal moveables will equally refift their be^ng moved,
if that they fliall bcmioved with cqual velocity : but jf one he
tobemovedmoiefwiftly than the other, it (hall make greater
fiftance, according to the greater velocity that fhall be conferred
on it. Thcfe things being premifed, let us proceed to the expla-
nation of our Problem \ and for the better underftanding. of
things, let us make a fliort Scheme thereof. Let two unequal
wheels be defcribed about this centre A, [in Fig, 7.] and let the
circumference of the lefTer be B G, and of the greater C E H an^l
k ^"^ii^i^liamcter A B Cj be perpendicular to the Horizon an^I

^A n ^r'""^' ^ ^"""^ ^' ^'"""^ '^g''^ '^"^d Tangents B F

and CL)v and in the arches BG and C E, take two equal parts
15 U and C E: and let the two wheels befuppofedto be turn (1

roun^l

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2°K.B. 9,163

DiALOGtaElIb

^oiind up^n their centres with equal velocities^ fo as that two mo-
^^ables, which fuppofe for example to be two ftoncs placed in the
pouits B and come to be carried along the circumferences B G
C E, with equal velocities ^ fo that in the fame time that the
ftone B (hall have run the arch B G, the ftone C will have paft the
^rchC E. 1 fay now, that the whirl or *z/ertigo of the leffer wheel
IS much more potent to make the pro)efiion of the ftone B, than
the <z/ertigo of the bigger wheel to make that of the ftone C.
Therefore the projeftion, as we have already declared, being to be
pude along the tangent, when the ftones B and C arc to feparatc
»rom their wheel- , and to begin the motion of projeftion from the
points B and C, then ftiall they be extruded by the impetm con-
ceived from the ^vertigo by (or along) the tangents B F and C D.
ine two ftones therefore have equal impetuoiities of running a«>
'ong the tangents B F and C D, and would run along the fame, if
tncy were not turn d afidc by fonie other force : u it not fo Ssr
gredifs >

S A G-R, In my opinion the bulinefle is as you fay.
8 A L V. But what force, think you, (hould that be which averts
f he ftones from moving by the tangents, along which tb^y arc ccr*
Mainly driven by the impetus of the ^vertigo, :

S A G R. It is either their own gravity, or elfc fomei glutuM^
matter that holdeth them faft and clofe to the wheels. yrrf r '
S A L v. But for the diverting of a moveable from the motion
to which nature incitcth it, is there not required greater or leffer
force, according as the deviation is intended to be greater or lef-
^ that is, according as the faid moveable in its deviation hath a
greater or leffer fpace to move in the fame time i

^ A G K. Yes certainly : for it was concluded even now, that to
P^^ke a moveable to move th'; movent vertue muft be increafed
*n proportion to the velocity wherewith it is to move.
^ A L V. Now confidef, that for the deviating the ftone upon
leffc wheel from the motion of projefiion, which it would
"^^ke by the tangent B F, and for the holding of it faft to the
"^cUicis required, that its own gravity draw it back the whole
^^"gth of the fecant F G, or of the perpendicular raifed from the
point G, to the line BF) whereas in the greater wheel iheretrafti-
needs to be no more than the fecant D E , or the pcrpendicu-
^J^lct fall from the tangent D C to the point E, leffe by much
F G, and alwayes leffer and leffer according as, the wheel is
tfj^ ^^igger. And foralmuch as thefe retraftions (as I may call
wh" 1 >"^quii ed tobe made in equal times, that is, whil'ft the
^ As pa(i^, j^^^ ^^^^j ^^^^^^ B G and C E, that of the ftone

Light to be more fwift tha
greater force will be rcqi

g r^Ai^- cne two equal arcnes d o anu cue none

th r\ retraaion F G ought to be more fwift than the o-

*^ E j and therefore much greater force will be required for

B b holding

194

G. G A L I L /E u s, his SyHemc.

holding faft the ftone B to its little wheel, than for the holding
the ftone C to its great one, which is as much as to fay, that Tuch
a fmall thing will impede the extrufion in the great wheel, as wiU
not at all hinder it in the little one. It is manifeft therefore that
the more the wheel augmenteth, the more the caufe of the pro- IJ
)edion diminiOieth. iflfl
S A G R. From this which I now underftand, by help of your mi'?^^
nute difleitation, I am induced to think, that I am able to faiisfi^
my judgment in a very few words. For equal impetus being iiH'
prcffed on both tht ftones that move along the tangents, by the
equal velocity of the two wheels, we fee the great circumferenccii
by means of its fmall deviation from the taagent, to go feconding>i
as it were, and in a fair way refraining in the ftone the appetite, i*>
Imay fo fay, of feparating from the circumference ^ fo that any
fmall retention, cither of its own inclination, or of fome glutina-
tion fufficeth to hold it faft to the wheel. Which, aaain, is not a-
ble to work the like effeft in the little wheel, which but little pr<i||
fecutingthedireftion of the. tangent, feeketh with too much ea^
gerneffe to hold faflr the ftone j and the reftrifiion and gUuinati^>q|
not being ftronger than that which holdeth the other ftone faft tM
* <;trappar U fa- the great it wheel, it ' breaks loofe, and runneth along the tan^
'tbeMli.*''^'^^^ gent, ' Jhereforc I do not only findc that all thofe have ertcdi
who have believed the caufe of the projeftion to incrcafe accor-
ding to the augmentation of .the vertigo's velocity j but I
further thinking, that the projeftion diminiOiing in the inlarging (M
the wheel, fo long as the fame velocity is reteined in thofe wheek^
it may poflibly be true, that he that would make the great wheel
extrude things like the little bne , would be forced to increafr
them as much in velocity, as they increafe in diameter, which be
might do, by making them to finifli their converfions in equW
times 5 and thus we may conclude, that the Earths revolution (m
viittgo would be no more able to extrude ftoncs , than any littl4
wheel that goeth fo flowly,as that it maketh but one turn in m^^m
ty four hours.

S A L v. We will enquire no further into this point for the pr<^'
Cent : Jet it fuffice that we have abundantly (if 1 deceive not ^1
k\f) demonftrated the invalidity of the argument, which at
fight feemed very concluding , and was fo held by very fanioi^^
men : and I (hall think my time and words well beftowed,
have but gained fome belief in the opinion of Simplicius^ I
not lay ot thc Earths mobility, but only that the opinion of fh^>f'^
that believe it, is not fo ridiculous and fond, as the rout of vulg^^
Philofophersefteemit.

SiMv. The anfwers hitherto produced againft the argume^^^

brought againft this D/iir»tf/ Re W«//(7A^ of the Earth taken ff^^

grav^

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2°K.B. 9,163

Dl ALOGUE. I L I^^

gi^avT bodies falling from the top of a Tower, and from pro;e^
^»ons made perpendicularly upwards, or according to any inclina-
l^onfidewayes towards the Eaft, Weft, North, South, &c. have
omewhat abated in me the antiquated incredulity I had conceived
^gainft that opinion : but other greater doubts run in itiy mind
at this very inftant, which I know not in the leaft how to free my
and haply you your felf will not be able to refolve thcmi
"ay )its poflible you may not have heard them, for they are very
n^odlerii. And thefe are the objeflions of two Authours, that cx

SK^r^ ^^'^^ ^^^"'^ ^^^^^^^ ^ 0.h.roH^aic.s

Phi r natural condufions 3 The reft are by a great both of two modem ^a-

^niiolopher and Mathematician, inferred in a Trcatife which he l^^icT''^
inal ^["^.^" favour of AnUotle, and his opinion touching the
th^ ^'^^y Heavens, where he proveth, that not onely

^ ejLomets, but alio thenewftars, namely, that anno 1572. in

f^/o;?e/^, and that anno 160^, mSagittarim were not above the
^pneres of the Planets , but abfolutcly beneath the concave of

«e Moon m the Elementary Sphere, and this he demonftrateth a-
gainlt Jycbo^ Kepler^, and many other Aftronomical Obfcrvators,
and beateth them at their own weapon *, to wit, the Dodrine of
Parallaxes. If you like thereof, 1 will give you the rcafons of
both thefe Authours, for I have read them more than once,
with attention and you may examine their ftreneth, and give
your opinion thereon.

S A L V. In regard that our principal end is to bring upon the

tw^Q T T^}^"' "^^^ ^""'^ ^^'^ ^g^inft the

^WoSyftemes, Ftolomaick,^ and Cofcrnican, it is not good to omit
any thmg that hath been written on this fubjeft.
in th"" T ^ therefore with the objedions which I finde

^ ^featifeof Concludons, and afterwards proceed to the
in the firft pi ace then, he beftoweth much paines in calcu- ^rfi chje-

^|Jt|gcxaaiy how many miles an hour a point of the terreftrial f/;; 'Ifl^iZ}
^ fituatc under the Equinoftial, goeth,*and how many miles tCuttU trJa •/
con^^ «ther points fituate in other parallels : and not being
the ^^^ir^^.^^ binding out fuch motions in horary times, he findeth
W th^ ^ minute of an hour j and not contenting Bimfelf

a minute, he findcs them alfo in a fecond minute 3 yea more,
W p'ainly, how many miles a Cannon bullet

^^^^ ^^^^ fame time, being placed in the concave of the Lu- , ,

it)t j^* PP^^'"{I^tallo asbigasCi?/?er«/V^iiimleJtrcprelenteth T^^mid fpc»d
mn^^ , ^^^^y fubterfuges from his adverfary. And havin^y '^'^c tha. fix dMjs
that a a ingenious andexquifite fupputation, he flieweth, Concave of th,

than C^^T^ '^'^^y f^"i"g ff^m thence above would confume more ^""^

todies naturally move. Now if by the abfolutc Divine ''Z

R K « dern Ant har of the

^ Power Conclufions.

G. G ALU jBus . his Sjfleine.
Power, or by fome Angel, a very great Cannon bullet were carr^
ed up thither, and placed ia our Zenith or vertical point, and from
thence let go at liberty, it is in his, and alio in my oftinion, a moft
incredible thing that it, in defcending downwards, fliould all the
way maintain It klf m our vertical line, continuing to turn roun4
with the Earth, about its centre, for lo many dayes, defcribiiif
under the Equinodial a Spiral line in the plain of the great circle
itlcif: and under other Parallels, Spiral lines about Cones, and
under the Poles falling by a fimple right line". He, in the neH
place,, ftabhlhctb and confirmeth this great improbability by vro\
*e way of interrogations, many difficulties impoffible t«
be removed by the followers of C.fer«.c«*i and they are, if ld<»
well remember . :

Sal v. Take up a little, good Simflicius, and do not load fli"
with foinany novelties at once : I have but a bad memory, ana
• therefore Imuft not go toofaft. And inregard it cometh into
my n»nde,that I once undcrtoolc to calculate how long time fuch a
grave body falling from the concave of the Moon, would be id
paffing to the centre of the Earth, and that I think I remembct
that the time would not be fo longj it would be fit that you fte(«
us by vvh^t rule this Author mide his calculation.

S 1 M P. He hath done it by proving his intent d fortiori^ a fufl*"
Cicnt advantage for his advcrfaries, fuppofing that the velocity of
the body filling along the vertical line, towards the centre of thf
Earth, were equal to the velocity of its circular motion, which

g"nd circle of 0,e concave of the l.^ZTo^
Which by equation would come to paffc in an hour, twelve thoO-
•fand fix hundred German miles, a thing which indeed ftvourso^
impoffibihty : Yet nevertheleffe, to ftew his abundan
and to give all advantages to his adverfaries, he fuppofcth it
true, and concludeth, that the time of the fall ought however
be more than fix dayes. °

Salv. And is this the fum of his method ? And doth he
this demonftration prove the time of the fajl to be above
dayes ?

Sagr. Me thinks that he hath behaved himfelf too modeftlfv^
for that having It in the power of his will to give what velocity b''
pJeafed to fuch a defcending body, and might afwell have made it
lixmoneths, nay, fix years in falling to the Earth, he is conten*
• with fix dayes. But, good Sal-vUtn^, ftarpen my appetite a li^'^
rSa.J[ ' ""^ what manner you made your computation,
fident "^T heretofore caft it up : for I am coO'

woTkirl 5^ '^^^^ queftion had not required lomd ingenuity
'S K, you would never have applied your minde un'"

SAt"'

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2°K.B. 9,163

I A L O G U E

II.

ip7

^ALv, IthnotQiioiighySagredm^ that the fiibjefts be noble
and great, but the bufiaeffe confifts in handling it nobly. And
who knoweth not that in the diffeflion of the members of
^ t>caft, there may be difcovered infinite wonders of provident
and prudent Nature^ and yet for onc) that the Anatomiift dif-
^efts? the biucher cuts up a thoufand. Thus I > who am now
leeking.how to fatisfic your demand^cannot tell with which of the
J^wofliapcs I had bcft to appear on the Stage j but yet^. taking
b^^rt from the example of SimpliciPtSylns Authour, I will, .with-
out more delays, give you an account (if I have not forgot) how
I proceeded. But before I go any further, I muft not omit to tell
yoUi th^it i nauchfear thait SimpltciHs h^th not faithfully related
l^hc manlier how this his Authour found, that the Cancon buU

in coming f\*oin the concave of the Moon to the centre of the-
Earth, would ipend more than fix dayes : for if he had fuppo-
that its velocity in defcending was equal to that of the
concave (a^v6"i>/]7//ri«if faith he doth fuppofe) he would have
ft^wn himfelf ignorant of the firft, and more fimple principles
of Geometry 'y'yesL I 2idmke that ShnpliciHSy in admitting the
ftippofition which he %eaketh of^ doth not fee the monflroas ab-
furdity thai t(i?? couched in it. s _

S I M i^. Its poflible that I may have erred in relating it , but
that I fee any fallacy in it, I am fure is not true. /• \mn ^ ,

SalV. Perhaps 1 did not rightly apprehend that which you:
faid, Do you not fay, that this Authour maketh the velocity
of the bullet in defcending equall to that which it had in tur-
ning round being in the concave of the Moon, and that com*
ming diown with the lame velocity, it would reach to the centre
mfixdaye^s^ ^ y.\y:i.ryjij -j^.^w

Si m p. So'is I thiiili'lie writeth.
^';SA t V. And do notyou perceive a fliamefull erroiir therein?
But queftionlcffe you diifemble it : For it cannot be, but fhat
you fliould know that the femidiameter of the Circle is lefle than
^"^^ fixthpartof the circumference; and that confequcntly, the err^^ sn'i>7'!irt
Jiniein which the moveable fliall palTe the femidiameter, fliallbe gHmemtaktHfrom
^^^l than the fixth part of the time^ in which, being moved ttf^MZ
^iththe fame velocity, it would palTe the circumference ^ and concave.
^hat therefore the bullet defcending with the velocity, where-
^>th it moved in the concave, will arrive in leffe than four hours
the centt-e , fuppofing that in the concave one revolution
J^^ldbe co4ilummate in twenty four hour^, as he muft of ne«
^^"^ty have fuppofcd it, for to keep it all the way in the fame
^^^^^c^lline. '

Simp, j<1(3^ I thorowly perceive the miftake : but yet I
^ould not lay ituponhimundefcrvedly, for its poffiblc that I

may

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2°K.B. 9,163

An exdSi ccfH'
futtof the time of
thffdll of the C-^'
MM bullet from the
Afoous concave to
theEdrths centre.

* The Author.

* By ihefe AfVi-
tings^ he every
where mcanes his
Dialogues, Demo-
r«,whichIpiomirc
to give you in my
lecond Volume.

Acceleration of
the natural motion
of grants hodies is
made according to
the odde number i
hgiuning at unity.

The ff0ces pajh

bj the falling
grave body are at
thtfejuaresofthtir
ttmei.

Ah intire a*>d
new Science of the
Academickfr;!,f^r-
fitng local motton'

G. G A L I L u s, hh Syficme.

may have erred in rehearfing his Argument, and to avoid running
into the lame miflakes for the future, I could wi(h I had his
Book 5 and if you had any body to fend for it, 1 would take it
for a great favour.

S A G R- You (hall not want a Lacquey that will runne for it
with all fpecd *: and he lhall do it prefently, without lofing any
time ; ia the mean time Salviatns may pleafc to oblige us with his
computation.

S I M p. If he go, he (hall finde it lie open upon my Desk?
together with that of the other Author , who alfo argueth a-
gainft CopernicHS,

S A G R. We will make him bring that alfo for tlie more cer-
tainty : and in the interim Sahiatm (hall make his calculation : I
have difpatch't away a mefl'engcr.

S A L V. Above all things it muft be confidered, that the jnotioO
of defcending grave bodies is not uniform, but departing from
reft they go continually accelerating : An cftcft known and ob-
fervcd by all men, unlefTe it be by the forementioned modern Av)-
thour, who not fpeaking of acceleration, makcthit even and U"
niforme. But this general notion is of no avail, if it be not known
according to what proportion this incrcafe of velocity is made
conclufion that hath been until our times unknown to all Philofo-
fhers\ and was firft found out &: demonftrated by the "Academicky
our common friend, who in fome of his * writings not yet publi{h'
ed, but in familiarity (heWn to me, and fome others of his ac--
quaintarice he proveth, how that the acceleration of the right mO'
tion of grave bodies, is made according to the numbers uneven
beginning abnnitate^ that is, any number of equal times being af-
figned, if in the lirft time the moveabk departing from reft (hall
have pxifled fuch a certain fpace, as for example, an ell, in the fe-
cond time it (hall have paifed three ells, in the third five, in the
foui'th feven? and fo progreffively, according to the following odd
numbers \ which inihort is the fame, as if 1 (hould fay, that the
fpaceir paflfed by the moveable departing from its reft, are untO< '
each other in proportion double to the proportion of the timeS)
in which thofe fpaces are mealured \ or we will fay, that tb^
fpaces pafled arc to each other , as the fquaresof their times.

S A G R. This is truly admirable : and do you fay that there
a N4athematical demonftration for it ?

S A L v. Yes, purely Mathematical \ and not onely for this, but
many other very admirable paflTions, pertaining to natural m<^'
tions, and to projefts alfo, all invented, and demonftrated by 0^^
Friend^ and I have fccn and confidered them all to my very great
content and admiration, feeing a new compleat Doftrine to fpring,
up touching a fubjeS, upon which have been written hundreds ot

Volumes ?

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2°K.B. 9,163

^99

D I A L O G U E. 1 L

Volumes, and yet not fo much as one of the infinite admirable
^onckifions that thofe his writings contain, hath ever been ob-
served, or undcrftood by any one, before Our Friend made
them out.

S A G R. You make me lofe the defire I had to underftand
more in our difpuies in hand, onely that I may hear Tome of
thofe demonftrations which you fpcak ofj therefore either give
them me prefeiuly, or at leaft promife me upon your word, to
appoint a-pairticular conference concerning them, at which Sitn-
fiiciH^^Mo ^\ay be prefent, if he fliall have a mind to hear the
pafliorts^nd accidents of the primary effeft in Nature.
^ S i M k: I. (hall undoubtedly be much pleafed therewith, though
indeed, 2[s to what concerneth Natural Philofophy, I do not think
that it is neceffary to defcend unto minute particularities, a gene-
ral knovvledg of the definitionf of motion, and of the diftin-
ftion of natural and violent, even and accelerate, and the like,
Sufficing ! For if this were not fufficient, I do not think that Art-
would have omitted to have taught us whatever inorel was
neceflary. : - ^ ' ' " '

' Sa l vj ft may be fo. But let tis not lofe more time about
thisj which I promife to fpend half a day apart in, for your fatis-
faSion V now I remember, I did promife you once before to
fatisfie yon herein. Returning therefore to our begun4:alcula-
tionof the time, wherein the grave cadent body would pafs from
the concave of the Moon to the centre of the Earth, that we may
iiot proceed arbitrarily and at randon, but with a Logical method,
^ewillfiift attempt loafccrtain our felves by experiments often
repeated, in how long time a ball v,g. of Iron defcendeth to the
t-arth fioman altitude of an hundred yards.

^AGR. Let us therefore take a ball of fuch a determinate
^^'gh^ and let it be the fame wherewith we intend to make the
computation of the time of defcent from the Moon.

S A L V. This is not material, for that a ball of one, often, of an
hundred, of a thoufand pounds, will all meafure the fame hundred
y.^^ds in the fame time.

M p. But this I cannot believe, nor much lefs doth AriftotU
[^«nk fo ^ who writeth , that the velocities of defcending grave
bodies, ate in the fame proportion to one another, as their gra-
Cities. .

^ L v. If you will admit this for true, SimpUcins, you muft be-
[^'"^ alio, ,hat two balls of the fame matter, bemg let fall in the ^J^:/;^^^^^^^

"^^ Q^oment, one of an hundred pounds, and another of one, diatomnve accor-

Zl^^i'^'^'^-oi^ at the ^;f;jf,;^^^^^^

ground, bctore the other is defcended but one yard onely : Now
^^"gyourfancy, ifyoucan, to imagine, that you fee the great

ball

The error of An-

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2°K.B. 9,163

2CC

(4)(^)N0Klhlt
thcfc Cakubtions
irc made in Itati-
weights and
mcafurcs^And i oo
pounds Haverdu'
fotfe make i ? i
Florentine. And
loo EngliHi yards
makfs i5c| Braces
Fiorent^ lb chac the
brace or y^r'^ o*^
our t/imhof is ~
of cur yard.

* The ItM/Unmcz*

fure which I com-
monly traiifl te
yards.

f The /tali4fim\\z

IS fly-*- of oiir mile.

G. Galilbus, htf Sjfleme.

ball got to the giouird, when the little one is ftill within lefstliail
a ^ard of the top of the Tower.

^ S A G R. That thispropofition ismoft falfc, I make no doubt in
the world i but yet that yours is abfolutely true, I cannot weU
affure my felf : neverthelel^ I believe it, feeing that you fo re-
folutely affirm it , which I am fure you would not do, if you had
not certain experience, or fome clear demonftration thereof.

S AL V. I have both .• and when we (hall handle the bufinefs
ot motions apart, I will communicate them .• in the interim, that
we may have no more occafions of interrupting our difcourfe vie
will fuppofe, that we arc to make our computation upon a ball of
Iron of an hundi^d C-*; pounds, the which by reiterated experi-
ments deicendcth from the altitude of an hundred (1, ) yards in
6ve lecond-minutesof an hour. And becaufe, as we havefaid,
the fpaces that are mcalured by the cadent moveable, incrcafe in
double proportion ; that is, according to the fquares of the times,
being that the time pf one hrft-minute is duodecuple to the time
ot hv? leconds, if we multiply the hundred yards by ,he fquare of
12, that is by 144, we (hall have 14400, which (hall be the num-
ber pt .yard$ that the fame moveable (hall pafs in one firft-minute
of an hour : and following th«? fame rule becaufe one hour is 60
minuter, niultiplying 1 440P, the number of yards paft in one mi-
nute, b^^thc fquare of 6y, that U, by 3600, there (hall come forth
5i84°,Q^«V the number of yards to be paged in an hour, which
make 1 7380 miles. Ar d delir.ng to know the fpace that the faid
ball w^uld pafs in 4 hours, let us multiply ,7180 by 16 rwbieh
is the fquar. of 4; and thep^odnfi will lL76^Clit^^KTb
nunxbef » much greater than the 4.ftance from ihe Lunar concave
to the ccntr. of the Earth which is but ^ 96000 miles" m Cl*
difta-nce of the concave 5 6 lemidiameters of the Earth, as that^mo-
dern Authpr doth ; and the leniidiameter of the Earth 3500 mile,,
of 5000 Braces tp» tmilc,whichareour //4/i^«milcs

Therefore, S^mfUfhts, that fpacc from the concave of the Moon
to the centre of the Earth, which your Accomptant faid couM
not be paired under more than fix days, you fee that (computing
by experience, and not upon the (ingers ends) that it (hall be paf-

1a ""i 11 h . ' computafion

exad, n (hall be paffed by the moveable in 3 hours, 22 p,i„ prim'
and 4 feconds. ' ^

J V * ^^l^""^ me of this ex-

calculation, tor it mult needs be very excellent.

,.y^\y- So indeed it is ; therefore having (as I have faid^ by

fheEP ''''' a moveabi; paffeth in its delint,

I0oyar4^ ate pjo-ed in 5 feconds i ,n how many feconds (haH

588000000

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2°K.B. 9,163

Dialogue. IL

588000000 yards (for lo many are in 56 diameters of the Earth)
oe paffed? The rule for this work is, that the third number muft
he multiplied by the fquarc of the fecond , of which doth come
14700000000, which ought to be divided by the firft, that is, by
loo, and the root fquareof the quotient, that is, 12124 is the
number fought, namely i2\i\min. fccnn, of an hour, which are
3 hours, 2 2 min, prim • and 4 feconds.

Sagr. I have fee n the working, but I know nothing of the
reafon for fo working, nor do I now think it a time to ask it.

S A L V. Yet 1 will give it, though you do not ask it, becaufe it
*A ^n^^ ^^fie. Let us mark thefe three numbers with the Letters
^.M, B fecond, C

201

100. 5. 588000000.

A B C 25

14700000000

241

12134

202

Cfc422

24240

^hird. A and Care the
numbers of the fpaces,
is the number of the
f»mei the fourth number
is fought , of. the time
alfo. And becaufe we
•^now, that look what
proportion the fpace A,
hath to the fpuace Cthe
fame proportion fliall the
fquare of the time B
have to the fqare of the
time, which is fought.
Therefore by the Golden Rule , let the number C be miilti-

•iV^^ ^he fquare of the number B, and let the produft be di-
vided by the number A, and the quotient fliall be the fquare of
the number fought, and its fquare root fliall be the number it fclf
ttiat is fought. Now you fee how eafie it i^o be underftood.

,8 A G R. So are all truths, when once they^re found out, but the
difficulty lyeth in finding them. I very well apprehend it,and kindly

^ank you. And if there remain any other curioGty touching this
P^IJ^t , I prj^y yQ^ jgj; hear it , for if I may fpeak my mind, I
Wnl with the favour of Simflicim^ that from your difcourfes I al-
^ayes le^m fome new motion , but from thofe of his Philofo-
pners , \ remember that 1 have learn't any thing of mo-

ment.

8alv. There might be much more faid touching thefe local
tic^\*^"^ 5 but according to agreement , we will referve it to a par-
^ conference ^ and for the prefent I will fpeak fomething
^uching ^1^^ Author named by Simplicins , who thinketh he hath
given a gr^at advantage to the adverfe party in granting that, that
fcc"d f^^llet in falling from the concave of the Moon may de-
with a velocity equal to the velocity wherewith it would

turn

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2°K.B. 9,163

The fd' lift m&ve"
Able if It move with
a decree of veioci-
ty ac^Hited in a
lil^e ttme with an
uniform rr.otior)^ it
jhali paf? a j^4f*
tbuffletothAt paf-
fed with the acce-
leratedmotiov.

A L I u s , bis Sjfieme.

turn round, ftaying there above, and moving along with the di-
urnal converfion. Now I tell him, that that lame ball falhng frota
the concave unto the centre 5 will acquire a. degree of velocity
much more than double the velocity of the diurnal motion of the
Lunar concave , and this I will make out by folid and not iuipef-
tineiu fuppoiitions. You muft know therefore that the grave
body falling and acquiring all the way new velocity according
to the proportion already mentioned , hath in any whatioevcr
place of the line of its motion fuch a degree of velocity, that if it
fliould continue to move therewith , uniformly without farther
cncreafing it j in another time like to that of its defccnt , it woul*'
palTe a fpace double to that pafTed in the line of the precedent
fliotiog of defcent. And thus for example , if that ball in coming
from the concave of the Moon to its centre hath fpent three hour^f
7. 1 min. frim, and 4 feconds , I fay, that being arrived at the cefl*
tre, it fhall find it felf conftituted in fuch a degree of velocity, that
if with that, without farther encreafing it, it ihould continue to
move uniformly , it would in other 3 hours , 21 min. prim. an<l
4 fecoi^ds , paffe double that fpace , namely as much as the whol^
diameter of the Lunar OrbV andbecaufe from the Moons coft*
cave to the centre are i j6coo miles , which the ball pafleth in 3
hours 2 3 frim- min. and 4 fecohds, therefore (according to wh^^
hath been faid) the ball continuing to move with the velocit
which it is found to have in its arrival at the centre , it woul
paffe in other 3 hours 22 min. prim, and 4 feconds, a fpace dou-
ble to that, namely 392000 miles ^ but the fame continuing '^^
the coi^q^yje of the Moon , which is in circuit 1 2 3 2000 miles, aii4
moving ihc^rewith in addiurnal motion > it would make in the
time :, that is. in 3 hours 2a min. prim, and 4 feconds, 17288*^
milesj wiich are fewer by many than the half of the 39200^^
miles. Vqu fee ^heSrhat the motion in the concave is not as th^
modern Author faith, that i^, of 1 velocity impoffiblcfor the ft"'
ing ball tq partake ofc C^^*- .

S A e R. The difcourfc Would pafs for current, and would gi^^
me full fatiiifadion, if that particular was but falved , of the n^^'
vingof the moveable by a double fpace to that paffed in falli^S
in another time equal to that of the delcent, in cafe it doth conti^^^
to move uniformly with the greateft degree of velocity acqu^*"^
in defcending. A propofition which you alfo once before fupp^'
^«d as true, but never demonftrated.

S A L V- This is one of the demonftrations of Our Friend^
you fliaU fee it in due time j but for the prefent, I will with (o^^^
con)ea:ures(not teach you any thing that is iiew,but)remember y^*^
of a certain contrary opinion,and (hew you,that it may haply io ^'
A bullet of lead hitnging in a long and fine thread faftencd to

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2°K.B. 9,163

Dialogue I L

roof, leaiove tar from perpcndiciikrity, and then let it go,
bvc you noc oblcrved that, k declining, will pafs freely, and well
near as far to the other lide of the perpendicular ? ' .

S A G R. 1 have obfcrved it very well, and had (f cfpecially if 6n
plummet be of any confiderable height) that it rifcth little leis
than it defcended, fo that I have fometimes thought^ that the a-
fccnding arch is equal to that defcending, and thereupon made it
a queftion whether the vibrations might not perpetuate themfclvesj
and 1 believe that they might, if that it were pofllble to remove
(he impediment of the Air, which refifting penetration, doth lome
fmall matter retard and impede the motion of the pencLdHm,
though indeed that impediment is but fmall : in favour of which
opinion the great number of vibrations that are made before the
J^^ovcable wholly ceafeth to move, leems to plead.

Sa Lv. The motion would not be perpetual, Sagredmy al-
though the impediment of the Air were totally removc4 beetle
there is another much more abftrufe,

Sagr. And what is that? a^fof my pact I can tJaiiak pf no

Other > ' " ''-^ " - ' '

S A L V. You will be pleafed wheh yon h<^c it> but^LiHilll |i6t
tell it you till anon : in the mean time, lei us proceed.. I have
propofed the obfervatioii of this FendHlnm^ to the intenri that you
fhould underftand, that the imfetHS acquired in the delccnding
arch, where the rpotioa is natural, is of it fclf able to drive the
faid ball with a violent motion, as fap on the other fide in the like
alcending arch if to, 1 ia.y, of it fclf, all external impedimems
heing removed : 1 believe alfo that every one take^ it for granted,
that as in the defcending arch the velocity all the Way increafeth,
^ill itcome to the lowcft point, or its perpendicularity r fo from
^his point, by the other alcending arch, it all the way diminillietli,
^"^till it come to its extreme and bigheft point : and dunmiftimg
^ith the fame proportions,whefewith it did before increafe, io that
the dgrees of the velocicieB in the points equidiftant from tk point
perpendicularity, are equal to eaah other. Henc^ it feemeth
ii>^(argaing with all due modefty) pbat I might ealily be indttced
^o l^elieve, that if the Terreftrial Globe were . bored thoipw the
centre, a Canon bullet defcending ihiough that Weil, would ac
^^lire by that time it came to the centr^:, fucb an impulie ot veio^
'^^y> that, it havincT paffed beyond the centre, would ipnng it up^
r;ds the other way, as -reat a fpace, as that was wherewith it had
<lefcended, all the way beyond the centre diminifhing the velocity
decreSirements like to the increafements acquired in the de-
• and the time fpcnt in this fecond motion ot atcent, I be-
^^e, Would be equal to the time of delcent. Now if the move-
by diminifliine.that its greate ft degree of velocity which it
^ Cc2 had

20|

The motion of
^rive penr^uli
miiht h perpetua-
ted , impediments
bsf^g removed.

If the Terreftrial
Globs were perfo^
tuted^ a ffraDe h^'
dy defcending by
that bore J vposld
fA^and afcerd as
far b.-yand the cen-
tre^ at it did dc'
fcend.

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2°K.B. 9,163

C. G A L I L u s, his Syjlcmc.

had in the centre, fuccefllvely until it come to total cxtinfiio/i)
do carry the moveable in fuch a time iuch a certain fpace, as it hail
gone in inch a like quantity of time, by the acquift of velocity
from the total privation of it until it came to chat its greatcft degree?
it feemeth very reafonable, that if it fliould move always with the
faid greateft degree of velocity it would pafs , in fuch anothcf
quantity of time, both thofe I'paces : For if vvc do but in our
mind fucceflively divide thofe velocities into rifing and falling I
degrees, as g. thele numbers in the margine 5 fo that the 2
firft fort unto 10 be fuppoled the increafing velocities, and the 3
others unto i , be the decreafing , and let thofe of the time 4
ofthcdefcent, and the others of the time of the afcent being 5
added all together, make as many, as if one of the two fums of 6
them had been all of the greateft degrees, and therefore the 7
whole fpace paffed by all the degrees of the increafing veloci- 8
ties, and decreafing, (which put together is the whole diame- 9
tcr) ought to be equal to the fpace paffed by the greateft velo- 1 0
cities, that are in number half the aggregate of the increafing
and decreafing velocities. I know that I. have but obfcurely 9
cxpreffed my felf, and I wifli I may be underftood. 8

S A G R. 1 think 1 underftand you very well i and alfo that I 7
can in a few words fliew, that I do underftand you. You had 6
a mind to fay, that the motion begining from reft, and all the ^
way increafing the velocity with equal augmentations, fuch as 4
arc thofe of continuate numbers begining at i, rather at o, 3
which reprefenteth the ftate of reft, difpofed as in the margine; ^
and continued at pleafure, fo as that the leaft degree may be o, i
and the greateft ^.^. 5, all thefe degrees of velocity wherewith
the moveable is moved, make the fum of 1 5 • but if the 0
moveable fliould move with as many degrees in number as
thefe arc, and each of them equal to the biggeft, which is 5, the
aggregate of all thefe laft velocities would be double to the
others, namely 30. And therefore the moveable moving with
a like time, but with uniform velocity, which is that of the
higheft degree 5, ought to pafs a fpace double to that which '^^
pafTetb in the accelerate time, which beginneth at the ftate of re/l»

Salv. According to your quick and piercing way of app^^^'
hending things, you have explained the whole bufinefs with iriOtc
plainnefs than 1 my felf ^ and put me alfo in mind of adding foii^c
thing more : for in the accelerate motion, the augmentation bc'
ing continual, you cannot divide the degrees of velocity, whic''
continually increafe, into any determinate number, becaufe char
ging every moment, they are evermore infinite. Therefore vve
{hall be the better able to exemplific our intentions by defcribi^^g
a Triangle, which let be this ABC, taking in the

Df A LOG U?. IL 205

fitle A as many equal parts as wc pleafc, A D, D E, E F, F G,
and drawing by the points D5EJF5G5 right lines parallel to the bale
^ C. Now jet us imagine the parts marked in the line A C, to be
^4ual times, and let the parallels drawn by the points D, E5 F5G)
reprefcnt unto us the degrees of velocity accelerated, and increaf-
ing equally in equal times , and let the point A be the ftate of reft,
from which the moveable departing, hath -i/. ^. in the time AD,
acquired the degree of velocity D H, in the fecond time we will
Alppofe, that it hath increafed the velocity from D H, as far as to
E 1, and fo fuppofing it to have grown greater in the fuccecding
tmics, according to the incrcafe of the lines F K, G C^^r. but ^^.^^
becaufcthe acceleration is made continually from moment to mo- ofiraveZdX^na-
^^^"t, and not disjunftl^ from one certain part of time to another^ tHraUr defcendent,
thepoint Abeingputfortheloweft moment of velocity, that is, Z7,^Mttm.mct,
for the ftate of reft, and A D for the firft inftanc of time follow-
'ng^ it is manifeft) that before the acquift of the degree of velocity
P H, made in the time A O5 the moveable muljt have paft by
infinite other lefler and leffer degrees gained in the infinite inftants
that are in the time D anfwering the infinite points that arc in
the line D A h therefore to reprefent unto us the infinite degaees
of velocity that precede the degree D H, it is rieceflary to imagiiie
infinite lines fucceflively leffer and leffer, which are fuppofed to
be diawn by the infinite points of the line D A, and parallels to ^
DH, the which infinite lines reprefent unto us the fuperficics of
the Triangle A H D, and thus we may imagine any fpace paffed
by the moveable, with a motion which begining at reft, goeth uni-
formly accelerating, to have fpent and made ufe of Infinite degrees
pf velocity, increafing according to the infinite lines that begin-
ing from the point A, are fuppofed to be drawn parallel to the
line H D, and to the reft I E, K F, L G, the motion continuing as
as one will.

Now let us complcat the whole Parallelogram A M B C, and let
prolong as far as to the fide thereof B M, not onely the Parallels
l^^arked in the Triangle, but thofe infinite others imagined to be
di^wn from all the points of the fide A C ^ and like as B C, was
*e greateft of thole infinite parallels of the Triangle, reprefent-
^i^g unto us the greateft degree of velocity acquired by the move-
^le in the accelerate motion, and the whole fuperficies of the faid
Triangle, was the mafs andfumof the whole velocity, wherewith
?^ ^hc time A C it paffed fucli a certain fpace, fo the parallelogram
1' a mafs and agereeate of a like number of degrees of vc-

^^g'e : and therefore if the moveable? that falling did make ufe

:2LC6

In nAturd Sci-
ences it i»' *lOt MC'

cejftiry to fetk^Ma-
tijentattvtUl evi-
denee.

7 hi pendulum
httn^in^ ttt a long-
er thretd^ makfth
its vthrations more
feUome thdn the
P'ndulum hanging
a 4 T^ orter threea.

The zihAtiots
of the jame pen-
cli'liim are made
wt'hths fame fn-
e^uenc) , whether
they he fmall or
great.

7he e an fe which
intpedeth the ren-
duluHi, ^nd re.'.U'
ceth it f rep»

G. G A L I L ^ u s , his Sjfieme.

of tlie accelerated degrees of velocity, anfwering to the triangle

A B Qhath paflld in inch a time fiich a fpaee, it is very reafonabk

and probable, that making ufe of the uniform velocities anfwering

to the parallelogram, it (hall pafle with an even motion in the

fame tune a Ipace double to that paflcd by the accelerate mo-
tion.

Sagr. I am entirely fatisficd. And if you call this a probable
Difcourfc, what fliall the neceffary dcmonftrarions be ? I wift
that in the whole body of common Philofophy, I could find one
that was b.ut thusconcludent.

Sim p. It is not necetfary in natural Philofophy to feek exqui-
fite Mathematical evidence. ^

Sagr. But this point of motion, is itliot a natural queftion?
and yet I cannot find that Anftotle hath demonftratcd any the
leaft ,accidcnt of ,t. B^t let us no longer divert our intended
Theme, nor do y9u faij, I pray you Sahiatus, to tell me that
which you hintf d to me to be the caufe of the fendHlums qui^'
cfcenc^ 5 befides the reliftance of the Medium ro penetration. '

Saj^v. Teyq[ie; of twqpe«^/i// hanging at unequal diftan"
ces^ dpth noc that which i^ faftned to the longer threed make it*
vibrations more feldome )
• 5 A G R. Yes, if they be moved to. squall diftances from theii
perjpendicularity. , ,

S-A i. V. This greater or leffe elongation importeth nothing at
all, for the fame pe«rf«//i/« alwayes uuketh its reciprocations in e-
quall times, be they longer or fliorter, that is, though thcpcndnhf^
be httle or much removed from its perpendicularity, and if they
are not abfolutely equal, they are inibnfibly different as expe-
rience may fliew you : and though they were very unequal, yet
would they not.di(countenance, but favour our caufe. There*
fore let us draw the perpendicular A B \jn Fi^.p.] and hang from
the point A, upon the threed A C, a plummet G, and another up-
on the fame threed alfo, which let be E, and the threed A G, being
removed from its perpendicularity, and then letting go the pluin-
mccs C and E, th-y (hall move by the arches C B D, E G F an<J
the plummet E, as hanging at a leffer diftance, and withall, ^
(by what you faid) Ieire removed, will retufn back again fafter»
and make its vibrations more frequent than the plummet C
therefore (hall hinder the faid plummet C, from running fo rnticb
farther towards the term D, as it would do, if it were free : an^
thus^e plummet E bringing unto it in every vibration continual!
iiixpedimcnr, it /hall finally reduce it to quiefcence. Now tb^
fame tbrced, (taking away the middle plummetj a compofitioO
r T]i^ S^^^'^ f that is, each of its parts is fuch a pendii^

Inm tiliiaed ncetci: and necrcr to the point A, and therefore difp^^'

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2°K.B. 9,163

Dialogue II.

fed tomakf it.> vibrations luccefiively more and more frequent i
arid coaicqueutly is able to bring a continual unpeditnent |o the
plummet C , and for a proof that this is lo, if we do but obtervc
the thread A C, we (hall fee it diftended not diredly, but in an
arch i and if infteadof the thread we take a chain, we ftalldil-
cern the effeft more perfeftly ; and efpccially removing the gra-
A^ity C, to a confidcrable diftance from the perpendicular A B, tor
that the chain beine compofed of many loofe particles, and each ot
them of fome weight, the arches A E C, and A F D, will appear
notably iacurvated. By reafon therefore, that the parts ot the
chain, according as they are neerer to th? point A, defire to make
cheir vibrations more frequent, they permit not the lower parts of
the faid chain to fwing fo far as naturally they would : and by
continual derraaing from the vibrations of the plummet C, they
finally make it ceaie to move, although the impediment of the air
■Wight be removed.

S A G H. The books are now come ; here take them SimflUim^
and find the place you are in doubt ot.

^n■S , M P. -See, here it is where he beginneth to argue againft the
idiarnal motion of.the Earth, behaving htft confuted the annual.
UotHs terra amum ajferere Co^crmczoos cogit con-verjiomm e.
jHfdem qmiidianam ; alias idem tcn^ Hemiff barium conttnenter
ad Sulem ej^ct converfum obumbrato femper averfo. [/» Engltjh
■thus : ] The annual motion of the Earth doth compell the Co-
ftrnicjns to alfert the daily converfion thereof i otherwile the
fame Hemifphere of the Earth would be continually turned to-
wards the Sun, the fliady fide being always averfe. And fo one
half of the Earth would never coirie to fee the Sun.

Salv. I find at the very firft fight, that this man hath not rightly
apprehended the CobermcanHyfothefts, for if he had but taken
notice how he alwayes makes the Axis of the terreftrial Globe
perpetually parali.l to it felf, he would not have fa.d that o^
l^^iroftheLrth would never fee the Sun, but that the f^^^
would be one entire natural day, that is , that thorow all parti ot
the Earth there would be fix moneths day, and fix monetbs night,
=»s it now befalleth to the inhabitants under the Pole , Dut let
this iniftike be forgiven him, and let us come to what remai-
neth. _

SiNvr. It followeth, Banc antcm 4^^'*:"''; Tf.^
M'Mc^u clfe fic demonAramu.. Which ipeaks in Enghfl, thus :
That thU gj ,-anon of the Earth is impolTible we thus demonftratc.
That which enfueth is the declaration of the following figure,
wherein is delineated many defcending grave bodies, and afcend-
»ng light bodies, and birds that fly toand agam in the air , &c.
Sa«r. Let us lee them, I pray you- Ohl what fine figures,

what

2c7

The thread or
chain to tvhich 4
pendulum u faft'
ned , mak^th an
arch^ and doth not
firetch it felfe
fireight out im itt
vihrationt.

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2°K.B. 9,163

aoS

•pcfci armai, or
arnun.

G. G A L I L u hh Syfleme.

wbat birds, what balls, and what other pretty things are here?

Simp. Thcle are balls which come from the concave offh^
Moon.

Sagr. And what is this ? .

Simp. This is a kind of Sheli-fifli , which here at Venice they
call buovoli ^ and this alfo came from the Moons concave.

Sagr. Indeed, it feems thcn,that the Moon hath a great poW-
croverthefe Oyfter-fiflies, which we call * armed fijhes.

Simp. And this is that calculation, which I mentioned, of this
Journey in a natural day, in an hour, in a firft minute, and in ^
fecond, which a point of the Earth would make placed under the
Equinoftial, and aUb in the parallel of 48 gr. And then followeth
thisj which I doubted 1 had committed fomc miftake in reciting^
therefore let us read it. His fofitis^ necejfe eff, terra circnlaritcT
ntota^ omnia ex aere eidenty Qjtod fi hafce piias ^quales p0'

nemas fondere^ magnitHdine^ gravitate^ ^ in conca^vo Spbara Lu^
narisfojitas libera defcenfm permittamns^ ft motum deorfum ^qn^'i
mits celerttate motui circnnt^ (quod tanien fecns efi^ cumpila
^c.) elabentnr minimnm (nt mnltHm cedamns adverparO^) d
fex : quo tempore fexies circa terram^ d^c. [^In Englijb thus*
Thefe things being fuppofed, it is neceffary, the Earth being cit
cularly moved, that all things from the air to the fame, &c. S?j
that if wefuppofe thefc balls to be equal in magnitude and gr^
vity, and being placed in the concave of the Lunar Sphere, ^
permit them a free defccnt, and if we make the motion do^^'
wards equal in velocity to the motion about, (which nevertheless
is otherwife, if the ball A, &c.) they (hall be falling at leaft (that
we may grant much to our adverfaries) fix dayes in which ii^^
they (hall.be turned fix times about the Earth, &c.

S A L V. You have but too faithfully cited the argument of thi^
pcrfon. From hence you may colled SimpUcins^ with what cau-
tion they oiight to proceed, who would give themfelvcs up to b^'
lieve others in thofe things, which perhaps they do not belieV^^j
themfelves. For me thinks it a thing impofliblc, but that this A^'
thor was advifed, that he did defign to himfelf a circle, whofcdi^'
meter (which amongft Mathematicians, is leffe than one third paf^
of the circumference) is above 72 times bigger than itfclf;
crrour that affirmeth that to be confiderably more than 3^?^?
which is leffe than one-

S A G R. It may be, that thefe Mathematical proportions, wbi^b
are. true in abftraft, being once applied in concrete to Phyfical an^
Elementary circles, do not fo exaftly agree : And yet, I think?
that the Cooper, to find the femidiametcr of the bottom, which
- \^ ^^^^ ^^^^ ^"'^ Mathematicians

in abltraa, although fuch bottomes be things meerly material)

an^J

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Dialogue.

3nd concrete : therefore let Sim^licins plead in CKCufe of this
Author i and whether he thinks that the Phyficks can differ fo
Very nuich from the Mathematicks.

S I M p. The fubftraciions are in my opinion infufficient to ialve
this difference, which is fo extreanily too great to be retonciled !
and in this cafe 1 have no more to fay bjt that , OHandoque bonm
dormitct Homerm. But fuppofing tlie Calculation of ^ Salz^iatm

be more exaft, and that the time of the delcent of the ball a^the L?dne
'Were no more than three hours j yet me thinks, rhat coming from >>•

concave of the Moon, which is fo great ^ diftance off, it would
If^'^anaditiirabie thing, that it fliduld have an inftinft of inaintain-
^^g itfclf all the way aver thefelf-fame point of the Earth, over
^mch it did hang in its departurfc' thence, and not rather be left a
^^^y great way behind '^-'ii^ c-^3iov r , >yonr o

S alv; Theeffeft may be admirable, and hoc admirable, but
"*tural and ordinary, according as the things precedent may fall
out. For if the ball (according to the Authors fuppofitions^
Whilft it ftaid in the concave of the Moon, had the circular motion
twenty four hours together with the Earth, and with the reft of
^he things contained within the faid Concave , that very vertud
which made it turn round before its defcent, will continue it in
the fame motion in its defcending. And fo far it is from not keep-
ing pace with the motion of theEarth^ and from ftaying behind,
that it is more likely to out-go it rbeiug that in its approaches to
*e Earth, the morion of gyratioil is to be made with circles con-
tinually leffer and Icffer ^ fo that the ball retaining in it felf that
elf-fame velocity which it had in the concave, it ought to antici-
^te, as I have faid, thc^vertigo or converfion of the Earth. But
^ the ball iiy the concave did want that circulation, it is not obli-
ged in defcending to. maintain it felf perpendicularly over that
P^mt of the Earth, which was juift under ic when the defcent be-
gan. Nqj. CopernzcHSj or any of his followers affirm the
*^nie.

Simp. But the Author maketh an objeftion, as you fee, de-
^ anding on what principle this circular motion of grave and light
oaies, doth depend : that is^ whether upon an internal or an ex-
ternal principle.

^^Salv. Keeping to the Probleme of which we fpeak, I fay,
^^t that very principle which made the ball turn round, whirft it
Y ^.^^ '^""^r concave, is the fame that maintaineth alfo the
mak* • in the defcent : yet 1 leave the Author at liberty to
^ ^t internal or external at his pleafure.
i I outward ^ ^'^^ Author proveth, that it can neither be inward nor

^ And! w^ilHay the

' ^ L Y. And! will fay then, that the ball in the concave did

D d not

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2°K.B. 9,163

4li

210

. IfTg Iftioxv no more

Mhs doi»' W*rds\
than feho n^aveth
fl:e Stays rcund^
nor k""^ ^"^
thi*>gof thefecMH"
fesy ntfi'ethan the
Karnes impofed en
them tj w.

G. G A L I L i?: u s , his SyfJeme.
not move, and fo he (hall not be bound to (hew how that in def-
cendingit continucth all the way vertically over one poinr. fof
that it will not do any fuch thing.

Simp.- Very well i Bat if grave bodies, and light can have no
principle, either internal or external of moving circularly, thaP
neither can the tcrreftfial Globe move with a circular motion: axjd
thus you have the intent of the Author.

S A L V. I did not fay, that the Earth had no principle, either
interne, or externe to the motion of gyration, but I fay, that I d9
not know which of the two it hath *, and yet my not knowing ^
hath not a power to deprive it of the famej but if this Author
can tell by what principle other mundane bodies are mqvcd rouO^J)
of whofe motion tlicre is ao doubt 1 fay, that that which 0^'
keth the Earth to move, is a vertue, like to that, by which Mat^
and Jupiter are moved, and wherewith he believes that the ftarry
Sphere it felf alfo doth move ^ and if he will but affure mc,who
the mover of one of thefe moveables, I will imdertake to be abl^
to tell him who makelh the Earth to move. Nay more ; I wil'
undertake to do the fame,' if he can but tell me, who movethtb^
parts of the Earth downwards. !

S I M r . The caufe of this is moft manifeft, and every one ksxo^
that it is gravity.

S A L V. You are out, Simflixius^ you (hould fay, that ever;
one knowes, that ic is called Gravity : but I do not queftion y^**
about the name, but the eiTence of the thing, of which effen<^
you know not a tittle more than you know the effence of
mover of the ftars in gyration j unleffe it be the name that ba^*
been put p this, and made famihar, and domeftical, by the mi^y
experiences which we fee thereof every hour in the day, : but tf^
as if we really underftand any more, what principle or vertue
is which moveth a ftone downwards, than we know who mov^*
it upwards, whenitis feparated from the projicient, or who ^
veth the Moon round, except (as I have faid) oncly the
which more particularly and properly we have affigaed to the tfiff^
tion of defcent, namely, Gravity \ whereas for the caufe of ^]
cular motion, in more general termes, we aflign the Vertue intp^\
fed^ and call the fame an Intelligence^ either aflifting, or inforipi^'
and to infinite other motions we afcribe Nature for their cauf^'

Simp. It is my opinion, that this Author asketh far leife
that, to which you deny to make anfwer j for he doth not ^
what is nominally and particularly the principle that "^^"fry
grave and light bodies circularly , but whatfoever it be, he d<^j ,
reth to know, whether you think it intrinfecal, or extrinf^^^
For howbeit, 'v.gr, I do not know, what kind of thing that gf^^* J,
is, by which the Earth defcendeth i yet I know that it is an '^^f^^-^

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2°K.B. 9,163

DiA

LOGUF.

2il

1^0

6l9

principle, feeing that if it be not hindered, it moveih fpontane-
oufly : and on the contrary, I know that the principle which mo-
Veth it upwards, is external j although that 1 do not know, what
thing that vertuc is, imprefled on it by the projlcient.

Sal V, Into how many queftions muft we excurre, if We would
uccide all the difficulties, which fucceflivcly have dependance on«
wpon another ! You call that an external (and you alfo call it a
preternatural and violent) principle, which moyeth the grave pro-
jeft upwards \ but its poflible that it may be no lefle interne and
natural., than that which moveth it downwards j. it may p jradven-
t^re be called external and violent, fo long as the moveable is joy-
ned to the projicient \ but being feparated, what external thing
remaineth for a mover of the arrow, or ball ? In fumme, it muft
^^^ccffarliy be granted, that that vertue which carrieth fuch a move-
iiole upwards, is no lefle interne, than that which moveth it down-
wards • and I think the motion of grave bodies afcending by the
'W'jptf/Wtf conceived, to be altogether as natural, as the motion of
Qclcent depending on gravity.

S I M p. I will never grant this j for the motion of defcent hath

principle internal, natural, and perpetual, and the motion of
^fcent hath its principle externe, vio.cnr, and finite.

S A L V. If you refufe to grant me, that the principles of the
Motions of grave bodies downwards and upwards, are equally in-
^^rnal and natural j what would you do, if 1 fhould fay, that they
alfo be the fame in number ?

Simp. I leave it to you to judge.
^ ^ But I defire you your felf to be the Judge ; Therefore
j.^^?^^'^^ you believe that in the fame natural body, there may
e interne principles, that are contrary to one another ?

^Mi>. I dovei;ily believe there cannot.
J. ^ALv. What do you think to be the natural indination of
^ ^rth, of Lead, of Gold, and in fum, of the moft ponderous mat-
that is, to what motion do you believe that their interne
P"^cipiedraweth them?

the ^ ^ ^' towards the centre of things grave, that is, to

no^f K^"^^^ Univerfe, and of the Earth, whither, if they be

^ Hindered, it will carry them,
aivd ^ ^ Terrefirial Globe were bored thorow,

a Well made that fliould pafle through the centre of it, a

^atur T ^^'^8 ^"^^ ^^^"^ moved by a

^ould ^"trinfick principle, would paffe to the centre , and it
cinU ^^^'^ this motion fpontancoufly, and by intrinfick prin-
^^^'^^itnotfo? ^
g^^P- Sol verily believe.

^ ^ V. But when it is arrived at the centre, do you think chat

Dd a it

Ihevertticipfhich
carrieth grdvepro'
jcHs upr^4fd's , is
H9 lejfe natural t9
them y tbdft tht
frravitj which rno-
veth them d9vfH'

Contr4ry prin*
ciples cannot nmn-
rally refide m tht
fame {ubjtS,

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2°K.B. 9,163

212 G. G A L I L i?: u s , SyfJeme.

it will paffc any further, or clfe that there it would immediately
ftand ftill, and move no further ?

S I M p. I believe that it would continue to move a great way
further.

S A L V. But thiv; motion beyond the centre, would it not be up-
wards, and according to your affcrtion preternatural, and violent
And yet on what other principle do you make it to depend, but
only upon the felf lame, which did carry the ball to the centre,
and which you called intrinfecal^ and natural ? Finde, if you Call)
another external projicient, that overtaketh it again to drive
upwards. And this that hath been faid of the motion thoroW
the centre, is alfo feen by us here above ^ for the interne impetus
JJ^VkZ^th^'it of a grave body falling along a declining fuperticies , if the fai^
^ that fuperficies be reflefted the other way , it fhall carry it, without »

which f^CAUeapr,
terJtAtural a»d vi- )

which it calledpre. iQt interrupting the motion, aUb upwards. A ball of lead that

angjeth by a threadi> being removed from its perpendicularity t> de'-
fcendeth fpontaneoufly, as being drawn by its internal inclination?
and without any interpofure of reft, palfeth beyond the lo\^^
point of perpendicularity : and without any additional mover?
moveth upwards. 1 know that you will not deny, but that th^
principle of grave bodies that moyeth them downwards, is no let'
natural, and intrinfecal, than that principle of light bodies, vvhick
moveth thfem upwards : fo that I propoic to your confideration *
ball of lead, which defcending through the Air from a great al^
titude, and fo moving by an intern -principle, and comming to *
depth of water, continueth its defcejiti and without any other
teriie mover, fubmergeth a great vvay ^ and yet the motion oi
defcent in the vvattr is preterf>atutal unto it i but yet neverthek^
dependetli on a principle thatis;nternal, and not external totk*^
ball. You fee it demonftrat^d then, that a moveable may
moved by one and the fame internal principle, with contrary

tipns.,.. , . . ;uMii'.i'.^ 'v; ^nii-,

S i m p, t believe therC; ^re Jolutions to all thefe cbjtStiOl^^
tliougii for the prefenti do not remember them ^ but however ♦
be, the Author continueth to demand, on what principle this^'r
cular motion of :^rave and light bodies depeiideth ^ that is ,
ther on a principle internal, or external j and proceeding
wards, fheweth,that it can be neither on the onc,nor on the o^^^^
faying i Si ai cxterno ^ Den/neiUHm cxc it at per continuum ^^''^
cnhmi an *vero Angeius^ an air } Et hunc qnidtm mnlti ^Sr
^a^t. Sed contra— [InEngliJh thus] If from an externe pf'^
ciplc V Whether God doth uot excite it by a continued Mira^^
or ail Angel, or the Air ? And indeed many do affign this. ®^
on the contrary

Salvv Trouble not your felf to reail his argumem j for 1

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2°K.B. 9,163

Dialogue

!Ji5

none of thofe who afcribe that piinciple to the ambient air. As
to the Miracle, or an Angel, I fliould rather incline to this fide ; for
that which taketh beginning, from a Divine Miracle, or from an
Angelical operation ■■, as for inftancc, the tranfportationof a Can-
non ball or bullet into the concave of the Moon, doth in all pro-
bability depend on the vertue of the fame principle for perform-
ing the reft . But, as to the Air, it ferveth my turn, that it doth
■ftot hinder the circular motion of the moveables, which wc did
foppofe tp move thorow it. And to prove that, it fufficeth (nor is
more required) that it moveth with the fame motion, and finifb-
e*h its circulations with the fame velocity, that the Tcrreftrial

Globe doth. ^

Simp. And he likewife makes his oppofition to. this alio ;
remanding who carrieth the air about, Nature , or Violence i
And proveth, that it cannot be Nature, alledging that that is con-
trary to truth, experience, and to Ct>psr«ic«i- himfelf. •

S A t V. It 1? not contrary to Copernicus in the leaft, who writetfa
no fuch thins i this Author afcribes thele rhingsto him witl?
twoexceflive courtei5e. It's true, he faith, and for my part I
think he iaitl* well, that the part of the air neer to the Earth, be-
ing rather a terreftrial evaporation, may have the fame nature,
»nd natu/ally follow its motion i or, as being contiguous to it,
ittay follow it in the fame manner, as the Peripateticks lay, that
The fuperio urpartof it, and the Element of Hre, follow the mo-
tion of the Lunar Concave, fo that it lyeth upon them to declare^
whether that motion be natural, or violent. ■
Simp. The Author will reply, that if CoferB/fK/maketh only
*he inferiour part of the Air to move, and fuppofeth the upper
part thereof to want the faid motion, he cannot give a reafon,hdW
that quiet air can be able to carry thofe grave bodies along with
«, and make them keep pace with the motion ot the t-ar th.

S A L V. CopermcHs will fay, that this natural propenfioa of the -^^^^^^
elementary bodies to follow the motion of the Earth, hatK a H-
"»«cdSphe5e, outof which fuch a natural inclmation would«eale, ^^^^^^ ^^^^ ^

^^^fideslhat, as 1 have faid, the Air is not ^^^'^'ZvJth T^l"'*'"
"moveables along with it, which being feparated from the Earth,
do follow its motion -, fo that all the objedions come to nothing,
«'hich this Author produceth to prove , that the A.r cannot caule

Simp. To (hew therefore, that that cannot be, it w.U be necet
*^*fy to fay, that fuch like cffefts depend on an interne pnncip e,
'gainft which pof.tion, oboauntHr difficiUun^, M tmxtnMs
l^'^fiion.s fecund^, of which fort are thefc that follow. Frinci-
t^miUHd wtem '^^d cfi acudcns, W fuhjianua. Si ptimnm -,
VKdtnam il[»d> nam nHalitas locmotiva ctrcHtn, haSlemt nulU

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2°K.B. 9,163

G. G A L I L ^ u s, hif Sylrmc.

videtiir dgnitj, (In Englijh thus:') Contrary to vVhich pofitiofl
there do aiife moft ditlicult, yea inextricable I'eco qiieftions,
luch as thefe *, That intern principle is either an accident, or a
fubftance. If the firft , what manner of accident is it ? For a
locomotive quality about the centre, feemeth co be hitherto ac-
knowledged by none.

S A L V. H0W5 is there no fuch thing acknowledged ? Is it not
known to us, that all thefe elementary matters move round, to-
gether with the Earth ? You fee how this Author luppofeth f^
true, that which is in queftion.

S I M p. He faith, that we do not fee the fame j and me thinks?
he hath therein reafon on his fide.

S A L V. We fee it not , becaufc we turn round together with
them.

Simp. Hear his other Argument. Qjt^ etiam fi ejfet^ qno^
nfodd tawen W'z/entretHrtnrcbfPS tarn contrarik } in ignc^ nt in ^'
qua \ in aere^ ut in terra ; in ^I'ventibus^ ut in animk carentibus ?

Englijh thus : ] Which although it were, yet how could it be
found in things fo contrary > in the fire, as in the water ? in the
air, as in the earth .> in living creatures, as in things wanting
life ?

S A L V. Suppofing for this time, that water and fire are contra*
ries i as alfo the air and earth \ (of which yet much may be faid )
the moft that could follow from thence would be, that thofe mo*
tions cannot be common to them, that are contrary to one ano-
ther : fo that ^.g. the motion upwards, which naturally agreetb
to fire, cannot agree to water h but that, like as it is by nature con-
trary to fire : fo toit that motion fuiteth, which is contrary to the
motion of fire, which fliall be the motion deorfkm-^ but the ciC'
cular motion, which is not contrary either to the motion furfutH)
or to the motion deorfkm^ but may mix with both, as AriHotlc
himfelf affirmeth, why may it not equally fuit with grave bodi^^
and with light ? The motions in the next place, which cannot be
common to things alive, and dead, are thofe which depend on the
foul : but thofe which belong to the body, in as much as it is ele'
mentary,and confequently participateth of the qualities of the ^'
Icments, why may not they be common as well to the dead corps?
as to the living body ? And therefore, if the circular motion
proper to the elements, it ought to be common to the mixt

bodies

^^GR. Itmuft needs be, that this Author holdeth, that a dead
cat, taliii^g from a window, it is not pofilble that a Hve cat alf^
could fall it not being a thing conveuient, that a carcafe fliou'd
partake of the qualities which fuit with things alive.

S A L V. Therefore the difcourfe of this Author concludeth

nothing

Dialogue II.

nothing againft one that fliould affirm, that the piiuciple of the cir-
cularmotfons of grave and light bodies is an intern accident .• I
know not how he may prove, that it cannot be a fubftance.

Simp. He brings many Arguments againft this. The firft of
^hich is in thefe words : Si fecund nm {nempiy ft dicas tale frinci-
finm effefHbftantiam) iUudefi aut utattrid, aut forma, ant cmpo-
fitum. i,ed repugnant ilerum tot diver f^ rerum natura, quales
ftim avcsjimaces^ faxa, fagitt^, ni-ver, fumi, graadines, fifcet,
&c. qu^ ttmtn omnia Jt>ecie & genere diferentia, moverentur a
itatHrafui cinnlariter, if fa naturK di'verfiffima, &c. [In Englifh
If the fecond, ^that is, if you fliall fay that this principle is
« fubftance) it is either matter, or form, or a compound of both.
But fuchdiverfe natures of things arc again repugnant, fuch as are
^«rds, foails, ftoncs, darts, fnows, fmoaks, hails, filhcs, 8ic. all
which notwithftanding their differences in fpecies and kmd, arc
moved of their own nature circularly, they bejng of their natures
moft different, &c.

S A 1. V If thefe things before named are of diverfe natures, and
things of divertc natures cannot have a motion in common, it niuft
if you would give fatisfa&on to all, that you are to think
of more than two motions onely of upwards and downwards : and
if there muft be one for the arrows, another for the fnails, another
for the ftoncs, and another for fifhen then are you to betliiuk your
felf of worms, topazes and muflirums, which are not lets different
in nature from one another, than fnow and hail.

Simp. It feems that you make a jeft of thefe Arguments.

S A L v. No indeed, Simfliciuiy but it hath been already an-
fw«cd above, to wit, that if one motion, whether downwards or
upwards, can agree with all thofe things afore named, a circular
motion may no lefs agree with them : and as you arc a Ftr.fate-
*''k , do not you put a greater difference between an ^kmentary
'ometand a cekftial ftar, than between a fifhand a bird ? and
>« both thofe move circularly. Now propofe your fecond .Ar-
gument.

S . MP. terra ftaret Per voUintatem Dei, rotartntne cetera, an
fi hocjalfumefi i naturi gyrare, ft lUud redennt prtorcs
iH^jiiines. Eifane mirum effet, qnod Oa'vta ftfctcnh, Alauda
'^idulo ^ lorvHS Itmact, fetraque, ctiam ''f ' '^J^'^;^
TH't- UVhichlthus render-:] Ifthc Earth be fuppofed to
ft»«d mil by the will of God, (hould the reft of bodies turn round
""l ? If not, then it's falle that they are revolved by nature •, ,f
other , the former queftions will return upon us. And
f'"ly it would be ftrange that the Sea-pie ftiould not be able to
hover over the fmall fifh, the Lark over her neft, and the Crow 0-
*cr the fnail and rock, though flyings

S A i v.

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2°K.B. 9,163

Gi^G A L I L /E LI s, his Sy 'Icm''.

'^5"?cVy. I would aiifwer for my felf in general tcims, that if
'it were appointed by the will of God, that the Earth fhould ceafe
. from its' diurnal revolution, thofe birds would do whatever fliould
•pleafe the 'fame Divine will. But if this Author deiire a more
'^articuliat anfwer, I fliould tell him, that they would do quire con-
trary to what they do now , if whilft they / being feparated from
theEarth , dobearthemfelvesupin thcair, the Terreftrial Globe
by the will of God, fhould all on a fudden be put upon a- precipi-
:*tate motion i it concerneth tliis Author now to afcertaift tis what
Would in this cafe fucceed.

S A ci r'-' I pray you, Sal'z^iatH.SySLt my rc<jdeft to grant to this
• Author; that the Earthftanding ftill by the will of God, the- other
"things, feparated from it, would continue to turn rotind of their
bwn natural motion, and let us hear what impofllbilirids or incon-
^feniences would follow : fori, as to my own particolar^do not
fee hoW there can be' greater diforders, than thele produced by the
Author himfelfj that is, that Larks, though they fliould ftie, couU
'not be able to hover over their nefts, nor Crows overfnails, or
"'^ocks from whence would follow, that Crows muft fuffer for
: Want of fnail$, and young Larkis muft die of hunger, and -cold, nO^
'treingable to be fed or flieltered by the wings of the old ones-
'This is all the? ruinethat I can conceive would follow, fuppofing
the Author^ fpeech to be true. Do you fee^ Simfltcius^ if grea^
ter iriccynveniences would happen ? , . . i: i i

S I M t>. 1 know not how to difcover greater •, but it is very ere-
dible, ^that the Author befides thete, difcovercd other diforders '^^
NatUf ^, Which perhaps in reverend ^efpefi of her, he was not will'
ing to inftance in. Therefore let^us^ proceed to the third Objc-
l^ion. Infnper qn} fit:, ut i^i^ fe5' tam varU tantum mo'veant^^
'dh &tcafu in Ortnm'^ parallels ad MqHatorem ? ut femper mo^eafi'
tHr^ nHnqnam qniefcant > [whkh fpeal^stothkfenfe:'^ Moreover?
, how comes it to pafs that thefe things, fo diverfe, are onely mov^d
from the Weft towards the Eaft, parallel to the iEquinoiSiaW
that they always move, and never reft ?

* Sal v. They move fiomWcft to Eaft parallel to the iEqui"
noftiar without ceafing, in the fame manner as yoir believe th^
fixed ftars to move from Eaft to Weft, parallel to the iEquinofti'
al, without ever refting.

y' Simp. Qjiare^ qudfuntaltidres^celeriks-, qnb h.Hmiliores^tar'
^'^ik's} (i.e.) Why arc the higher thefwifter, and the lower tb^
flower ? v. ioV3l '

S A L V. Becaufe that in a Sphere or circle, that turns about up'
''6n its own centre, the remoter parts defcribe greater circuits, and
'the parts^eater at hand defcribe lefTer in the fame time.
Si MP' Qjiare^ MquinoSiiali propriores^ in majori

remotioreS'^

Dialogue II.

^emtiorcs^ in minori circulo fentfHur } [fcilicet:'] Why are
thole near the yEquinoaial carried about in a greater circle y and
thofe which are remote in a Icfler ? -

A LV. To imitate the ftarry Sphere, fti which rhofe'neareft
t® -the Equinoctial V move in greater circles, than the niore re-
mote. ^ a.;-^ .■ . .. r ^ . . _ . - -.J - - -

''^i u ri'^'tQ2i4'fe F'd^^ ^^^^ circa centrnm

teri^yafjtlitu maxima^ teleritate ^ M ^^^^ '^^^^ ^^^^^

cmritm propium, gyro-mlloy tarditate fnprema val<z/entur>
[TW ^ vVhy is the lame ball under the Equinoftial wholly
intned rouiiJ^he centre of the Earth in the greateft circumfe-
mnce, with anincrediblc celerity ^ but nnder the Pole about it^
owncentre^ in-nocircuite,but with the ultimate degree of tar-
^ty itdj.ihi-// (3Lfh -iol ,. - ... . -'--••^

SalvV- To irtiitatbtfieftarsof the FiHrifiament, thatAVOulddo
^he like if thry had the diurnal motion.

Simp. Ouare cadem res, pila ^. g.plumbea,, fi femel terram
circui'vit^ dehcnpto circulo maximo^ eandem uhiqHe non citmni-
^grn Ccmndkmcirculmt maximn^^^^ fedtranflata extra ^^ui^o^
^talem zn ciraulis minorihm agetur } [IVhtch fpe^k^th thks :
Why doth not the fame thing, as^for example, a ball of lead
turn round every where according to the fame great circle, if once
defcribing a great circle, it hath incompalfed the Earth, but being
temovcd from the Equinoaial, doth move in leffer circles >

Salv. pecaute fo would, nayr according tb the dodrine ot
^tolomey, fo have iome fixed ftars done, which once were very
«ear the iEquinoftial, and defcribed very vaft circles, and now that
they are farther off, defcribe leffer. '

S ag-r. If 1 could now but keep in mind all thefc fine no^
^^ns , I (hould think th^t 1 had made a grcac purchaie i I muft
^ceds intreat you, Simplicius, to lend me this Book, for there can-
not chufe but be a fea of rare and ingenious matters contained in
it.

Simp. I will prelent you with it.

Sagr. Not ib, Sir i 1 would not deprive you of it : but arc
^l^e Qtieries yet at an end ? .

Simp. No Sir ^ hearken therefore. Si latio ctrcHlans gra^
"^ibm^ U^.b^s cfinatHralk.qnaUsejlcaqH^fitfecHndHm Itne^
r^eiam } Islam fi natHralk, quomodo & k motus qm ctrcntn eli,
""^'^rali, eft, ckm Ihci. differ at a re^o > St ^toUntn^, qui Jit, ut
"^'IP^^ igmtnm furl urn eJlans fantiUofHm caput fur fum a terra,
""'"'^^^^murcL iol^z^atnr^&c. [_lVhtcbtake tn our idiom :^ If
^circular lation is natural to heavy and light things, what is that
^hich is made according to a right line ? For if it.be natural, how
^hen is that motion which is about the centre natural^ feeing it

E e differs

Of the mxt mo-
tion XV e fee r.st the
j)a>t thM IS crew
lar , becanfe rte
fart. ike thereof.

G. G A L I L ;e u s , bis SjlJeme.

difFcrs, in fpecies from a right motion ? If it be violent, how is
tlutafiery dart flying upwards, fparkling over our heads at a di-
ftance from the Earth, but not turning about, d^c.

S A L V, It hath bcai faid ahcady very often, that the circular
motiojn is natural to the whole, and to its parts, whilft they are in
perte^i: dilpofure , and the right is to reduce to order the part?
diforde.fed j though indeed it is better tp fay, that neither the
parts ordered or dilbrdered everihove with a right .motion, but
with one mixed, which might as well be averred meerly circular:
but to us but one part onely of this motion is vifible and obfer-
vable, that is, the part of the right, the other part of the circular
being imperceptible to us, becaufe we partake thereof i j And thii*
anfwejs tp the rays which mov^ upwards^ and round about, but we
cannot diftinguifli their circular motion, for that, with that we our
felves move alio. Bu*I believe that this Author never thought
of this mixture j for you may iee that he r^folutcly faith, that the
rays go direfily upwards, and not at all in gyration.

Si mp» Qjiare centrum Jph^re clehpfie fub ^qu a tore jpiram de-
fcnbit m ^jm piano : fub aliis paraUelk jpiram defcribit in conol
fub Polodefc&ndit in axe lineam gyralem^ decnrrens in fnperjici^
cylindrica confignatam ? (\n Englifli to this purpofc: ) Why doth
thic centre of a falling Globe under the ^Equinoftial defcribe ^
fpiral line in the plane of the ^Equator and in other paralk'^
a Ipiral about ^ Cone ^ and under the Pole defccnd in cb^
axis d^fpfibing a'gyral line, ruifning in a Cylindrijal Superfi'

S^ Lv. Becaufe of the lines drawn from the Centre to the cif'l
cumferenceof the fphcre, which are thofe by which ^r^^^j d^'
fcend , that which terminate? in the i^quinoaial defigneth a cir-
cle, and thofc that terminate in other parallels defcribe conical
fuperficies \ now the axis delbribeth nothing at all, but continuetb
in its own being. And if I may give you my judgment freely? ^
will fay, that I cannot draw from all thefe Queries, any fenfe fha^
interfcreth with the motion of the Earth j for if I demand of tb'^
Author, ('granting him that the Earth doth not move) what woul^
follow in all thefe particulars, fuppofing that it do move, as
pernicm will have it j 1 am very confident, that he would fay tha^
all thefe effefts would happen, that he hath objcded, as incunvc-
niences to difprove its mobility : fo that in this mans opinion
ceffary confequcnccs are accounted abfurdities : but I befc^^''
y^^iif there be any more, difpatch them, and free us fpcedil/
trom this wearifom task.

S i m p. Id this whicU follows he oppofes Copernicus & his Seftatof^?
who affirm,thatthe motion of the parts feparated from their whol^'
is dnely to unuc themfelves to their whole j but that the moving

circularly

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2°K.B. 9,163

Dialogue. 11.

circularly along with the vcrtigcnous diurnal revolution h abfo-
lutely natural : againft which he objcdeth, faying, that according
to thcle mei;S opinion Si iota terra^ nna cum aqua in nihilnm
redigerctnr-i fjulla granclo ant pln^'ia e nnbe rlccideretj fed natn-
raltter tantiim circumferetnr , neqne ignis hUhs^ ant ignenm afcen*
deret^ckm illonim non improbabili fententia ignis nullns fit fnpra.
[Which 1 tranflate to this fenfe: ] If rhe whole Earth, together
with the Water were reduced into nothing, no hail or rain would
fall from the clouds, but would be onely naturally carried round j
.neither any ti;e or fiery thing would afcendjfeeing to thcfe that men
it is no improbable opinion that there is no fire above.

Sal v. The providence of this Philofopher is admirable, and
worthy of great applaufc^ for he is not content to provide for
things that might happen, the courfe of Nature continuing, but
will (hew hie care in what may follow from thofc things that he
Very well knows fliall never come to pafs. I will grant him there-
fore, (that I may get fom pretty paflages out of him) that if the
Earth and Water (hould be reduced to nothing, there would be no
niore hails or rain*?, nor would igneal matters afcend any longer
upwards, but would continually turn round : what will follow >
what will the Philofopher fay then ?

Simp. The objeftion is in the words which immediately fol-
low i here they arc : Qutbrn tamen experientia ratio ad'ver^
fjttnr. Which ncverthclefs (faith he) is contrary to experience and
reafon.

S A L v. Now I muft yield, feeing he hath fo great an advan-
tage of me as experience, of which I am unprovided. For as yet
I never had the fortune to fee the Terreftrial Globe and the ele-
inencof Water turnd to nothing, fo as to have been able to ob-
f<^rve what the hail and water did in that little Chaos. But he
perhaps tells us for our inftru£i:ion what they did.

Simp. No, he doth not.

S A L Y. I would give any thing to change a word or two with
this perfon, to ask him, whether when this Globe vaniflied, it car-
ried away with it the common centre of gravity, as I believe it did j

which cafe, I think that the hail and water would remain infen-
fate and ftupid amongft the clouds, without knowing what to do
^ith themfelves. It might bealfo, that attrafted by that great
y^id VacHHrn, left by the Earths abfenting, all the ambients would

rarificd, and particularly, the air, which is extreme eafily drawn,
and Would run thither with very great hafte to fill it up. And
perhaps the more folidand material bodies, as birds, ("for there
)vould in all probability be many of them fcattered up and down

the air) would retire more towards the centre of the great va-
cant fpherc (for it feemeth very reafonablc, that fubftances that

Ee 2 undet

G. G

A L I L /E U S

under fmall bul

his 5):/

erne.

contain

ces afligncd them, leaving the more Ipacioiis to the more raritie ,
and there being dead of hunger, and rcfolved into Earth, would
form a new little Globe, with that little water, wliich at that time
was among the clouds. It might be alio, that thofe matters as
not beholding the light, would not perceive the Earths departure,
but like blind things, would defcend according to their ufual cuftotn
to the centre, whither they would now go, if that globe did not
hinder them. And laftly, that 1 may give this Philofophcr a IcfjJ
irrefolute anfwcr, 1 do tell him, that 1 know as much of what
would follow upon tl>e annihilation of the Terrcftrial Globe, as
he would have done that was to have followed in and about the
fame, before it was created. And bccaufe I am certain he will
fay, that he would never have been able to have known any of
all thofe things which experience alone hath made him knowing
in, he. ought not to deny me pardon, and to excufe me if 1 knoviT
not that which he knpws, touching what would enfue upon the
annihilation of the faid Globe : for that I want that experience
which he hafh. Let us hear if he have any thing elfc to fay.

S I M F- There remains this figure, which reprefcnts the Terrc-
ftrial Globe with a great cavity about its centre, full of air j an^I
to (hew that Gra'ves move not downwards to unite with the Tcf'
reftrial Globe, as Coper/ticu^ faith, he conftituteth this ftone in
ihe centre o and demandcth, it being left at liberty,what it woul^l
do ; and he placeth another in the fpacc of this great vacuum, and
asketh the fame queftion. Saying, as to the firft : Lapis in centro
confijtHtm, ant ajcendet ad terram in punaum aliquod^ ant non. Si
fecundHm ', falfnm eSi, partes ob folam fejnneiionem a toto, adil'
Ind mover I. Si primnm omnis ratio experientia renititnf^
neqne grazfia in fude gra^u it atis centro conquief cent. Item fi fw
Jpenfm lapis ^ liberal us dccidat in centrum^ feparabit fe a toto^ con*
tra Copcrnicum : ft pendcat^ refragatur omnis experientia^ cftf^
^vidaamm int:gros fornices corrnere, (^Wherein he faith : ) The
ftone placed in the centre, either afcendeth to the Earth in fome
point, or no. If the fecond , it is falfc that the parts feparated
from the whole, move unto it. If the firft ^ it contradifieth all
reafon and experience, nor doth the grave body reft in the centre
' of its gravity. And if the ftone being fufpended in the air, be Jet
go, do defcend to the centre, it will feparate from its whole, con-
trary to CopcrnicHf : if it do hang in the air, it contradifteth all
experience : ftnce we fee whole Vaults to fall down.

S A L y. I vvill anfwer, though with great difadvantage to i^y
felf, feeing 1 have to do with one who hath feen by experience?
what thefe ftonesdo in this great Cave : a thing, which for f^l
part I have not feen and vvill fay, ihat things grave have an c^^'

ftence

much matter, (hould have narrower pla*
the more fpacious to the* morp rarirtcd)

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2°K.B. 9,163

Dialogue IL

ftencc before the common centre of gravity : fo that it is not one
centre aloncvvhich is no other than indivifible point, and therefore
of no efficacie,that can attraft nnto it grave matters j but that thole
matters confpiring naturally to unite, form to themfelves a com-
mon centre, which is that about which parts of equal moment
confift : fo that 1 hold, that if the great aggregate of grave bo-
dies were gathered all into any one place,the fmall parts that yvere
feparated from their whole, would follow the fame, and if they
were not iVmdered, would penetrate wherever they fliould find
parts lets grave than themfelves ; but coming v^here they ftiould
meet with matters more grave, they would defcend no farther.
And therefore I hold, that in the Cave full of air, the whole Vault
would pt cis, and violently reft it felf onely upon that air, in cafe
its hardnefs could not be overcome and broken by its gravity ; but
loofe ftories, I believe, would defcend to the centre, and not fwim
above in the air : nor may it be faid, that they move not to their
^holc , though they move whither all the parts of the whole
would transfer themlelves, if all impediments were removed.

Simp That which remaineth, is*a certain Errour which he ob-
ferveth in a Difciplc of Cofeninuf, who making the Earth to
move with an annual motion, and a diurnal, in the fame manner
as the Cart-wheel moveth upon the circle of the Earth, and in it
felf, did conftitute the Tcrrettrial Globe too great, or the great
Orb too little ; for that 365 revolutions of the i^quinoftial, are
kfs by far than the circumference of the great Orb.

Salv. Take notice that you miftake , and tell us the direft
^^ontrary to what muft needs be written in that Book j for you
fliould Tay^ that that fame Coperaicafi Author did conftitute the
Terreftrial Globe too little, and the great Orb too big ; and not
^Jie Tcrreftrial Globe too big, and the annual too little.

S I M The miftake is not mine ^ fee here the words of the
Book. No,2 <vidct, quod 'vcl circnlum annnum ^qno mtnorem, ^el
""'hem terreUm jnfto multo fabrket majorem. (In Englith thus ;)
W^fceth not, that he either maketh the annual circle equal to the

'^fi^, or the Terrcftrial Orb much too big.

Salv. I cannot tell whether the firft Author erred or no, lince

^he Author of this Traaate doth not name him i but the error ot
^his Book is certain and unpardonable, whether that tollower ot
^^^r;;;.«, erred or not erred -, for that your Author palfeth by fo
f ^terial an error, without either deteaing or correftrng it. But
l^-^m be forgiven this fault, as an error rather of inadvertencic,
^'^^"ofany tiiineelfe : Farthermore, were it not, that I am al-
^^^dy wearied and tired with talking and (pending fo much time
^Jth very little profit, in thefe frivolous janghngs and alterca-
^^^^^s, I could flicw, thatitisnotimpoflible for a circle, though

nc^

22t

Thi*f(rt grave are
before the centre of

The great mafi
of ^rave l^odies he-
ing transferred out
of their place the
feparated parts
vpoftld follor^ that

G. G A L I L u s, bis Sylctn^.

ft if ret imyffl ■
i-le with th^ cir-
CMTnfsrer.ee of a
[wall circle jtvt
times rivolved to
meafure And de-
fcrthe d hr.e hijlger

f/i- vrhatfoever.

no bigger than a Cart-wheel, with making not 3d^5,

Gond '^a.

*" The name of
the j^mhor is Set'
p:9 paramontim.

but IcfTe than

2o revoiu:ions, to defcribe and meafure the ciicumfercncc, not
ondy of the grand Orb, but of one a thoufand times greater 5
and this 1 f y to flicw, that there do not want far greater fubtil-
ties, than this wherewith your Author gocth about to dctcft the
'tha-^ .injure At eir- ertour of CoferHicjis I but I pray you, let us breath a little, that
lo We may proceed to the other Philofophcr, that oppofeth of the
fame Copernicus.

S A G R. To Gonfeffe the truth, I ftand as much in need of re-
fpite as either of you •, though 1 have oncly wearied my eares •
and were it not that I hope to hear more ingenious things froiu
this other Author, I queftion whether I fliould not go my ways, iO
take the air in my * Pleafure-boat.

Simp. Ibelieve that you will hear things of greater, moment j
for this is a moft accompliflied Philofopher, and a great Mathema-
tician, and hath confuted Tycho in the bulineffe of the Comets?
and new Stars.

S A L V. Perhaps he is the fame with the Author of the Book,
called Antt'Tycho ?

Simp. He is the very fame : but the confutation of the nevV
Stars is not in his Anti' tycho^ onely fo far as he provcth, that they
were not prejudicial to the inalterability and ingenerability of thC
Heavens, as I told you before but after he had publiflied bis
Anti'Tycho^ having found out, by help of the Parallaxes, a way
demonftratc, that they alfo are things elementary, and contained!
within the concave of the Moon, he hath writ this other Book?
de' tribns Ho^is Stcllis^ and therein alfo inferred the h^^^'
ments againft Copernicus : I have already (hewn you what
harh written touching thefe new Stars in his Anti-Tycboj where
denied not, but that they were in the Heavens j but he proved,tb^
their produftion altered not the inalterability of the Heavens, an^l
that he did^with a Difcourfe purely philofophical,in the fame nian
ner as you hav-r already heard. And I then forgot to tell you, hov^
that he afterwards did tinde out a way to remove them out of

the

Heavens j for he proceeding in this confutation, by way of con^'

putations and paiallaxes, matters little or nothing at all under-

ftood by me, I did not mention them to you, but have bent all i^^Y

ftudies upon thefe arguments againft the motion of the E^^^^^

which are purely natural.

S A L V. I underftand you very well : and it will be convenient

after we have heard what he hath to fay againft Copernicus^ tb^i^

we hear, or fee at leaft the manner wherewith he, by way of

raIlaxes,proveth thofe new ftars to be elementary, which fo m^J^y

famous Aftronomers conftitute to be all very high, and among^

the ftars of the Firmament ^ and as this Author accompliflieth i^^^

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2°K.B. 9,163

DialogueII. ^^3

ancntcrprizc of pulling the new ftars out of heaven, and placing
them in the elementary Sphere, he Oiall be worthy to be h.ghly
exalted , and transferred himfelf amoogft the ftars , or at lealt,
that his name be by fame eternized amongft them. Yet betore we
enter upon this, let us hear what he allcdgeth agamft the opunon
of Copcnucu^, ar.d do you begin to recite his Arguments.

Simp. It will not be neceflary that we read them ad 'verbum,
becaufe they are very prolix ; but 1 , as yon may lee, m reading
them feveral times attentively, have marked in the margine thole
words, wherein the ftrength of his arguments lie, aiad it will
faffice to leadthem. The firft Argument beginneth here. B.t J'-^rf-/
prima, f, opimo CoPcrmct recipiatur , Cntcrmm natnralK FMo- ^r^^;^, ,^cn...
fophU, nt prorfus toUatur , -vthcmcntcr jaltem lalefa^ari ,f Phihfopk;
'"id.tnr. [In our Idiom thus] And firft, if Copcmc;** his opinion
beimbraced, the Crinrnm of natural Philofophy will be, it not
wholly Subverted, yet at leaftcxtrcamlyniaken. ^ ,

- Which, according to the opinion of all the lefe of Ph.Iofophcr.
•cquire.h, that Senfe and Experience be our guides m phi lolopha-
tixig : But in the Copcr.ican^6uotx the Senies are greatly delu-
ded, whil'ft that theV vifibly dilcover neer at hand m a pure A/.rf/-
nm the eraveft bodies to delbend perpendicularly downwards, ne-
ver deviating a tingle hairs breadth from reaitudei andyetaccor.
dine to the opinion oiCopcrnicm, the fight m fo manifeft a thing
is deceived , and that motion is oor reall ftraight, but mixt of

tight and circular- . „ i ^ t j

Sa L V. This is the firft argument, that ArtjiotU, Pfotej, and
all their followers do produce; to which we have abundant-
ly anfwcred , and (hewn the Paralogifme , and with fufficient
Plamneffe proved, that the motion in common to us and other mo-
veables, is a« if there were no fuch thing i but becaufe true con-
-lufion: me t wiS a thoufand accidents, tlut confirme them, I
Will, with the favour of this Philofopher addc ^^^^^^^ —

>tid yon SintPUc^s perfonating him, anfwer me to what I (hall
ask vou : And tirft tell me, what elFca hath that "on^^P"" ^f"' Jbe argument
which falling from thc.top of the Tower, i» the caule tH» you per-
cciveth motion for if" its fall doth operate upon you neither f^^^^^
more nor lefTe, than ks ftanding ftill on f^^^^^^'l^""^^^^^^^ ^"U
doubtleitecould not d.fcern its deicent, or diftinguilh us moving

from its lying ftill. . i^^i^n to the Tower,

Si M p.. I comprehend Its moving, in rciii ,

f-rthati fee it one while juft againft fuch a mark m the faid

Tower, and another while againft another lower, and fo fuccef-

fively , till that at laft I perceive it arrived at the ground

S . t. V. Then if that ftone were let fall from the tallons of an

Eagle flying, and £hould defccnd thorow the fimple mvifibleAjr,

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2°K.B. 9,163

274

anayouhaa no other object viUble and 11

comparifons to that, you could npt perceive its motion?

Simp.' No, ilor the ftone it IHf ; tor if I would fee it, when
it is at the higkft,.! muft raile up my head, and as it dcitcndetb,
Imuft hold it lower and lower,, and in a word, muft C(Wltinually
move either that, or myLeyG?,ifolfowing the^motion of the laid
ftone. : * jv/ ^'.?iiY:^n . ;:r it :

ihe motion of ' ^ ^ ^^^^ '-^^^ ^^^^ rightly anfwered;: you knovAr-then that
the eje arjfufth ^hc ftonc fycth ftill,- vvhcn without moving your eye, you alwayes
'\' aTkd ^^^'i^ '^^^^"^ y and you know that it moveth, when for the
. _cc ..^ ... keeping it in fight, you muft move the oi^gan of fight, the eye.- So
then when ever without moving, your eye, you contimially be-
hold an objea in the id f lame afpeft, you do always jud^c it
immoveable- • -.--^ ^
S I M V. I think it mitft needs be fo.

S A L V. Now fancy your ielf to Be in a (hip, and to: hifvc fkcd
your eye on the pomt of th^ SaiKyard : Do you think, that be^
caufe tlie.fliip moveth very taft, you muft move your eye, to keep
your figk alwayes upon the point of the Sail-yard, and to fal-
low its motion ? V

:S I M p.vl am certain, that 1 flibuld need to make no change at
all V and trhat not only in the figKi ^ but if I had aimed a Muskec
at it, Iftiould never have need^' let the fliip move how it will?
to ftir ican hairs breadth to_keep it full upon the fame.

Salv. And this happens becaufe the motion, which the Sbip
conferreth on the Sail-yard, it conferreth.alfo upon you, and upon
your eye^ lo that you need nor ftic it a.jot to behold the top of
the Sail.yard: andconiequently, it will feem to you immover
able. Now this Diicourlc being applied to the revolution of the
Earth, and to the ftone placed in the top of the Tower, in which
you cannot difcern any motion, becauie that you have that mo-
tion which is neccffary for the following of it, in common with it
irom the Earth fo that you need not move your eye. When
gainthej|^s conferred upon it the motion of defccnt, which is its
particuIaFmotion, and not yours, and that jt i. intermixed with the
circular, that part ot the circular which is common to the fton^?
and to the eye, continueth to be imperceptible, and the right on^'
ly is perceived, for that to the perception of it, you muft follow it
with your eye, looking lower and lower. I wifli for the undecei-
^rex'^enm'nt ^^"^ this Philofophcr, that I c^buld advile him, that fome tii«^
th\i Jh^Sh'^how ^'^.^^tlier going by water, he would carry along with him a Vc0
the common motion oi rearoiiablc dcpth full of water, and prepare a ball of wax,
u^impercpn^lc. other matter that would defcend very (lowly to the bottome,

that in a minute of an hour, it would fcarce fink a yard ; and that
rowing the boat as faft as coiJd be, fo that in a minute of an ho^'

^i^l ey.ce 'he mo-
tion of a cadetit bo
dy U foUeclsd,

Dialogue IL

2.25

it (hould run above aa hundred yards, he would ct the ball fub-
merge into the vvater,8c freely dcfcend,& ^J^f "^'y .'"'^'^'7/^^„";,°:
tion If he would but do thus,he fliould lce,firft,that would go in a
direa line towards that point of the bottom of the veflel,wh.cher ic
would tend,if the boat (hould ftand ftilU & to his eye, and in rela-
tion to the veffel, that motion would appear moft ftra.ghc and per-
Pendicular,and yet he could not fay , but that it wouIdi,e compofed
of the right motion downwards, and of the circular about the ele-
ment of\ater. And if thefe things befall in matters not natural
and in things that we may experiment in the.r ftate of reft , & then
again in the contrary ftate of motion, and yet as to appearance no
diverfity at all is difcovered, & that they feera to deceive our fenle
what can we diftiniiuini touching the Earth, which hath been per-
petually in the fame conftitution, as to motion and '^ft ^ A"^^^^^
what time can we experiment whether any difference is dilcernable
amongft thefe accidents of local motion, in its diverfe ftates of mo-
tion and reft, if it eternally indureth in but one onely of them ?

S A o K. Thefe Difcourfes have fomewhat whetted my ftomaclc,
which thofe fifhes, and fnails had in part naufeated; and the former
made „.c call to minde the correffion of an errour, that hath fo
much app arancc of tru^h, that 1 know not whether one of a
roufanKuld refufe to'admit it as unqueftionable. And it was
this^ that failing into Syria, and carrying with me a very good
-r^lefcope, that had been beftowed on me by our Conmon Fnend
who not many dayes before had invented, I propofed to the Ma-

riners, that it would be of great benefit in Navigation to make ute
of it ^pon the round top of a (hip, to difcover and k^nne Veffds
afar off. The benefit was approved, but there was objefted the
difficulty of ufina it, by rcafon of the Ships continual fluftuationi „,^^,,„v,,

/■ • ,1 ° 1 ^ where the aeitation IS lo much tmsthe foffihlH}

atid elpecially on the round ^r^^^^^"^'^^^^^ make ^/-'/-^ feeler-

greater, and that it would be better for any one tn ^^^^ ^ .^^ ^ ^

ufethereoftoftandatthePartnersupontheupper Deck wh^^^^^

the toffing is leffe than in any other place of the f . » (^''^^ "-"^
Will not conceal my errour) concurred in the fame opinion, and
for that time faid no more : nor can I tell you by wha bn^ I wa^
moved to return to ruminate with my felf upon th>s bufind^^^^^^
.n the end came tod.fcover my fimpljcity alth^ e f able)^in
admitting that for true, which is moft falfe ^^f 'J^^^^ ,1^^

gteat agitation of the basket or -J^ °Pj;^;3d render the

i'i>^a\l one below, at the partners ot ^he Malt, i

"fc of the Mcofc more difficult in finding out the objed.

S . , I (iould have accompanied the Manners, and your felf

sTm And fo (hould 1 have done, and ftill do : nor can I be-
lieve, if I (hoald think of it an hundred years, that I could under-
hand it othcrwifc.

rotind to? of the
UMaf of a {kh.

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2°K.B. 9,163

>A GR

G. G A L I L ^ u s , his Sjjleme.
I may then,it fecms,for once prove a Mafter to you botlt

*I deviate htie
from the drift Sea
Dialleift , which
Hcnominotcsalldi-
Uanccsby Leagues.

'Different mcti'
o»s depending on
the jluQuation of
the ski;.

* Greco , which
the Lacine Traii-
flator according to
his uliial careltHc-
neiic (to call it no
worle ) tranflatcs
Coram Ver.ium ,
the NoiihwcU ■
Windi iat Centum
Lilnnotum.

7n« nmttuitns
miiie in the TeU-
feope,depe«diri ox
the tg'titionoj the
Ship.

• This is a Cafile
fix Italian miles
from Venice
Northwards,

ZJnnerocL* itg*
r.a , the black or
paring of a nail.

J i_ r " .^^...ojiui uui-c piovc a Maiter to you botrt

And becaufe the proceeding by interrogatories doth in my opinion
much dilucidate things, befides the plealbre which it affords of con-
toundmg our companton,forcing from him that which he thouehthe
knew not I will make ule of that artifice. And firftj fuppofe that the
Sh.p,Gally,or other Veffel,which we would dilcover, is a great way
oft, that IS, four, fix, ten, or twenty » miles, for that to kenne thofc
neer at hand there is no need of thefe Glaflbs : & confequently,the
Idefcop may at fuch a diftance of four or fix miles conveniently
difcover the whole Veffel, & a muchgreater bul.'-. Now I demand
what tor fpecies, & how many for number are the motions that arc
made upon the round top,dependingoi, the fluftuation of the Ship.

S A L V. We will fuppole that the Ship goeth towards the Eaft-
Firft, ,n a calme Sea, .c would have^o other mot.on than
h,s of progreffion, but adding the undulation of the Waves,
thereftall refult thence one, which alternately hoy ftii g and M
enng the poop and prow, maketh the round top, to ean forward^
and backwards , other waves driving the veffel ^^aJZXZ .V.
Maft to the Starboard and Larboard ; others, may bring the (hiP
lomewhat abovt, and bear her away by the Mifnc from Eaft, one,
while towards the ' Northeaft, another while toward the South'^
eaft i others bearmg her up by the Carine may make her onely W
rile, and fall i and . n&m,thefc motions are for fpecies two, oB«
that changeth the d.re&on of the Ttlcfc^f, angularly, the othe^
hneally w.tW changing angle, that is , alwayes keeping thd
tube of tlie Inftrument parallel to its felf. Keeping

J^Tc next place, if we, having firft dircftea

theTe/r/c.p. yonder away towards the Tower of * fiLiVfii
mrfcs from In:nce,do turn it angularly to the right hand, orTo' the
left, or elfe upwards or downwards, but a»ftraws breadth what rf"
teft lhall It have upon us touching the finding out of the faid tower?
S A L v. It would make us immediately loic fight of i t for fuc

thoutndf of yardT^'' ''"^ ' "''^ '''"^ anJ

Sage. But if without changing the angle , keeping the tube
alwayes parallel to it felf, we ftould transfer it ten or twelve
yards farther off to the right or left hand , upwards or downward',
what alteration would it make as to the Tower >

S a L V The change would be abfolutely undifcernabic 5
that the fpaces here and there being contained between paralle
became , '"""^•on^ ™f<^f here and there, ought to be equal, and
^ecanfe the Ipace which the Inftrument difcovers yonder, is cap*"
V ^^"y °f thofe Towcrsi therefore we fhall not lofe fight ofit-

firm'thaS'theT,'''^"^ """^ '''^^'''P' '"^y undoubtedly
hrm, that the Te/e/c.f. moving to the right oi- left, upwards,

dott'P'

I ALOGUE.

II.

i27

ft.

tJownwards, and alio forwards or backwards ten or fifteen fathom.

allel

jfclf, the

(c ray cannot

Itraytrom ihe point oblcrved in the objcft, more 'than thofe fif-
teen fathom ; and becaufe in a diftance of eight or ten miles, the
Inftrument takes in a much greater fpace than the Gaily or other
Veffdkennd:, therefore that fmall mutation fhall not make me
lole il^ht of her. The impediment therefore, and the caulc of
ioling^hc objea cannot befall us, unleffe upon ihe mutation made
angularly fince that Te/e/^r?^^/ tranfpor ration higher or lower, to
the right, or to the left, by the agitation of the (hip, cannot import
any great number of fathomes. Now fuppofe that you had two
■^^lej€opes fixed, one at the Partners clofe by the Deck, and the o-
ther'at the round top, nay at the main top, or maid top-gailant
^op, where you hang forth the Fen?w?i or ftr^amcr, and that they
both dlreftcd to the Veflcl that is ten miles off, tell me, whe-
ther you believe that any agitation of the (hip,& inclination of the
Maft,caivmake greater changes,as to the angle,in the liigher tube,
-than in the lower ? One wave aiiling, the prow will make the m^in
top give back fifteen or twenty fathom moic than the foot of the
Maft,and it fhall carry the upper tube along with it fo greata ipace,
& the lower it may be not a palm^ but the angle fiia:! change in one
Inftrnment afwcll as in the other ; and likewife a fide-billow fl.all
bear the higher tube an hundred times as far to the Larboard or
Starboard, as it will the other below j but the angles change not at
^11, or elfe alter both alike. But the mutation to the right hand or
left, forwards or backwards, upwards or downwards, bringeth no
i'enfible impediment in the kenning of objefts remote, though the
alteration of the anele maketh great change therein h Therefore it
«^uft of neceffity be'confeffed, that the ufe of theTelefcope on the
'•ound top is no more diiKcuk than upon the Deck at the Partners 5
feeing that the angular mutations are alike in both places.
S A L V. How much circumfpedion is there to be uled in affirmmg
denying a propofition? I fay again,thar hearmgit rcfolutely attir-
*^ed, that there is a greater motion made on the Mafts top, than at
it^^ partners, every one will perfwade himfelf, that the uje ot the Jc-
^'f'ope is much more difficult above than below. And thus alio 1 w
excufe thofe Philofophers, who grow impatient andfly out into
P^fl^on aeainft fuch as will not grant them, that that Cannon bullet
^hich they cleerly fee to fall in a right line perpendicularly, doth
^^^^^lutely move in that manner ^ but will have its motion to be by
f^^^ch, and alfo very much inclined and tranfverfal : but let us
them in thefe labyrinths,and let us hear the other objeftions,
our Author in hand brings againft Coperntc^.
^ I M P. xhe Author goeth on to demonftrate that in the Do-
^"neof Copertiirm, it is requifite to deny the Senfcs , and the
' \ 2 grcatelt

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2°K.B. 9,163

128

tion of the F.'i th
tnnfl ca:ife ^ pfr-
petuai And firo»g

7 he Mir alwayej
touching tu """th
the fame part cf it
cannot maks
feel it.

ffethat rfillfcl"
low Copernicus ,
muSt deny hi6 fer.'

G. G A L I L ^ u s, hU Syjlcmc.

greateft Senfations, as for inftance it would be, if we that feci the
refpirations of a gentle gale, ftiould not feel the impulfc of a per-
petual winde (hat beateth upon us with a velocity that runs more
than ^$29 miles an hour, for fomuch is the fpace that the centre
of the Earth in its annual motion patfeth in an hour upon thecir*
cumfcrence of the grand Orb, as. he diligently calculates^ and
becaufe, as he faith, by the judgment of Copemtcm^ Cum terra
movctur circumpofitus aer^ motus t amen ejus ^ qjelocior Licet ac tn-
pidior ceUrrimo qHocunqne ^ento^ a nobis non fentiretur^ fed fnm'
ma fnm tranqHilttas repntaretnr^ nift alius motus accederet. Qnt^
eji ^erb decipi fenfum^ nifi h^ec ejfet deceptio ? [U'hich I mal^e to
fpsakjo this fenfe.~j The circumpofed air is moved with the Earth,
yet its motion, although more fpeedy and rapid than the fwifteft
wind whatfoever, would not be perceived by us, but then woulcJ
bethought a great tranquillity, unleffe fome other motion fliould
happen 3 what then is the deception of the fenfc , if this be
not ?

Salv. It muft needs be that this Philofopher thinketh, that
that Earth which Copemicm makethto turn round, together with
the ambient air along the circumference of the greatOrbjis not that
whereon we inhabit,but fome other feparated from thisjfor that this
of ours carrieth us alfo along with it with the fame velocity, as al'
fo the circumjacent air : And what beating of the air can we feel?
when we fly with equal fpeed from that which fliould accoft us ?
This Gentleman forgot, that we no Icfs than the Earth and air arc
carried about, and that confequently vvc are always touch'd by
one and the {ame part of the air, which yet doth not make us fe^l

Si mp. But I rather think that he did not fo think j hear the
words which immediately follow. Pr^terea nos qnoque rotamti'^
ex circumdH^ione terra d^c.

Salv. Now I can no longer help nor excufe him , do yo^
plead for him and bring him off, Simplicim.

S 1 M p. I cannot thus upon the fudden think of an excufe that
pleafeth me.

Salv. Go tor ^ take this whole night to think on it, and dc'
fend him to morrow j in the mean time let us hear fome other
his objedions.

Simp. He profecuteth the fame Objcfiion, fliewing, that in
way of CopermcHSj a man muft deny his own fenfes. For th^^
this principle whereby we turn round with the Earth, either
intrinfKck to us, or external j that is, a rapture of that Earth ^
if It be this fecond, we not feeling any fuch rapture, it muft
conteffed th^c (^^^^ feeling, doth not feel its own obje<3:

touching it, nor its imprefllon on the fenfible part : but if thepri^'

cipk

Dialogue. 11.

tiplc be intiiafccal, wc ftall not perceive a local motion that is de-
rived from oiir fclves, and we fliall never diicover a propcnfion per-
petually annexed to ourfelves.

S A L V. So that the inllancc of this Philofopher lays its ftrefs up-
on this, that whether the principle by which we move round with
theEarth.bc either extern, or intern, yet however we muft per-
ceive ir, and not perceiving it, it is neither the one nor the other,
and therefore wc move noti'nor confcquently the Earth. Now 1
fay, that it may be both ways, and yet we not perceive the fame.
And that it may be external ,t he experiment of the boat fupera-
bunuantly fatisticth mc I fay, fuperabundantly, becaufe it being
in our power at all times to make it move, and alio to make it
ftand ftili, and with great exaftncfs to make obfervation, whether
foinc diverfity that may be comprehended by the fcnfe of feci-
^^g. we can come to know whether it moveth or no, feeing that
yet no fuch fcience is* obtained : Will it then be any matter of
wonder, if the fame accident is unknown to us on the Earth, the
which may have carried us about perpetually, and we, without our
being ever able to experiment its reft ? Yon, Sim plicius^ as I be.
lieve, have eone by boat many times to f and if you will

confefs the truth, you never felt in your felf the participation of
that motion, unlcfs when the boat running a-ground, or encoun-
tring fome obftacle, did ftop, and that you with the other Paffcn-
gers being taken on a fuddens were with danger over-fet. It
Would be ncceffary that the Terreftrial Globe fliould meet with
fome rub that might arreft it, for 1 alfure you, that then you
would difcern the impulfe refiding in you, when it (hould tofs you
towards the Stars. It's true, that by the other fenfes, but yet
affifted by Reafon, you may perceive the motion of the boat, that
with the fiPht, in that you fee the trees and buildings placed on
^he (hoar, which benn^ feparated from the boat, feem to move the
contrary way. But if you would by fuch an experiment receive
intirefatisfaftionin this bufinefs of the Terreftrial motion, look
«nthc ftars, which upon this reafon feem to. move the contrary
^ay. As to the wondering that we (hould not feel luch a prm.
^iple,fuppofingit to be internal, is a lefs reafonable conceit ^ ior
if we do not feel fuch a one, that cometh to us from without,
^nd that frequently gocth away, with what reafon tan we expert
feel it, if it immutablv and continually refidesm us .> Now let

fee what vou have farther to allege on this argument.
Simp. Take this (hort exclamation. Ex hac ttaqnc op^nto^
dtffidercnofins JcnftbHS.HtpcmtHsfaUacibHS ^elftHpidf6

'J^^tem 1},,^,, fofTHmJis a facnltate adeo faUact ortnm trahenum^
[Which 1 render thusH From this opinion likcwife, we muft ot
^ nece(rity

239

Our motion may
he either i»terne or
extern'^ and yet
we never ferceive
or feel tt.

Themotiofi of a
goat infenfthle to ^
thofethat are vith
in it ^ at to the fenfe
of feelirg-

The hoAts msti'
on it ferce^tible to
the fiaht jojn*d
with reafon.

The terreftrial
motion colleHed
from tht /fars.

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2°K.B. 9,163

2 jc G. G A L I L /E u his Sy^cmc.

neccflity fufpeS: our own ienfes, as wholly fallible, or ftupid ijj
judging of fenfible things ^ven very near ac hand. What trnt"
therefore can we hope for, to be derived from fo deceiveable a ft'
culty ?

S A L V. But I defire not to deduce precepts more profitable, or
more certain, learning to be more circumfpeft and leis confident
about that which at tirft blufh is reprefented to us by the fenfo
which may eafily deceive us. And 1 would not have this Authot
trouble himfelf in attcmptiug to make us comprehend by fenlt^j
that this motion of delcending Graves is fimply right , and of
no other kind \ nor let him exclaim that a thin^ fo clear, manifeft)
and obvious fliould be brought in queftion j for in fo doing,
maketh others believe , that he thinketh thofe that deny that mO'
tion to be ablolutely ftreight, but rather circular, the ftone did
fenfibly fee it to move in an arch,feeing that he inviteth their fenfts
more than their Reafon, to judg of that cffeft : which is not true,
Simplicimj for like as I, that am indilSerent in all thefe opinio i
ons, and onely in the manner of a Comedian, perfonate Coperni*^
CHS in thefe our reprefentations, have never fecn, nor thougli^
that I have feen that ftone fall otherwife than perpendicularly^
fo I believe, that to the eyes of all others it feemed to do the
fame. Better it is therefore, that depofing that appearance in
which all agree, we make ufe of our Reafon, cither to confirm the
reality of chat? or to difcover its fallacy.

S A G R. If I could any time meet with this Philofopher, who
yet me thinks is more fublime than the reft of the followers oi
the fame doSrines, 1 would in token of my afFcSion put him '^^
mind of an accident which he hath doubtlefs very often beheld'
from which, with great conformity to that which we now difcourf^^
of, it may be collefted how eafily one may be deceived by the bar^
appearance, or, if you will, reprefentatiori of the fenfe. And th^
accident is, the Moons feeming to follow thofe that walk the ftreefs
in the night, with a pace equal to theirs, whilft they fee it go gli'
ding along the Roofs of houfes, upon which it flicweth juft like ^
car, that really running along the ridges of houfes, leaveth theU*
behind. An appearance that, did not reafon interpofe, would b^^
too manifcftly delude the light.
jrgumenti a- S I M P. Indeed there want not experiments that render us cc^'
^^/«y? theEmks tain of the fallacy of the meer fenfes j therefore fufpending ftich
mouon taken , cx fc^fatious for the prcfcnt, let us hear the Arguments that follo^.

Which are taken, as he faith, ex rernm uatnra. The firft of whici*
is, that the Earth cannot of its own nature move with three
ons \iery different j or Otherwife we muft deny many manifc'^
Axioms. The firft whereof is, that Om/ik ef^Sius depetideat
aliqnacaHfa ; [i.^.] that every effeft dcpendeth on fome caofr'

The

Three Axiomt
thut are fHppofed

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2°K.B. 9,163

DialogueII.

The fecond, that NuUa resfeipfam prodncat ; [/. e-] that nothing
produceih it felf from whence it follows , that it ,s not pofli-
ble that the mover and moved fliouldbe totally the fame thing :
And this is raanifeft, not onely in things that are moved by an cx-
trinfick mover; but it is gathered alfo from the piinciples pro-
pounded that the fame boldeth true in the natural motion depen-
dent on an intrinfick principle; otherwife, being that the mover,
as a mover, is the caufe, and the thing moved as moved, is the
cffea , the fame thing would totally be both the caufe and effed.
Therefore a body doth not move its whole felf, that is, lo as
that all moveth , and all is moved ; but its neceffary m the thing
moved to difiinguiftiinfome manner the effiaent principle ot the
motion, and that which with that motion is moved. The third
Axiom is, th^ttnrtb^qH^fenfHifKhjktHntHr, nnHm, qHate^^
nnnm, nnam foUm rem frodncat ; i.e. That m things fubjed to
the fenfes , one, as it is one, produceth but onely one thing : That
is, the foul in animals produceth its true divers operations , as the
fight, the hearing, the Imell, generation, C^^. all theje with
feveral inftrumits. -^^^f^^^t^^^^::^

tLfiSTauf^^^^

Win be a thing very manifeft , that one fimple body , as is the
Earth , cannot of its own nature move at the fame time with
three motions, very divers: For by the foregoing fW^^^^J
all moveth not its felf all ; it is nccclTary .therefore to diftinguifli
in it three principles of its three motions ; otherwife one and the
fame principle would produce many motions ; but if tt contem in
it thr4 principles of natural motions , bcfides the part moved , it
fliallnot bea fimple body, but compounded of three principle
movers , and of the part moved. If therefore the Earth be a fim-
Ple bod; t Aal not move with three motions ; nay more, . will
HOC mov'e' w tfany of thofe which Copcrnu»s afcnbeth to u , it
being to move but with one alone, for that it is '
reaLs o( AnfioUc , that it moveth to «^ '^^"^'X Spherical
fliew , which defcend at right angles to the Earths Spherical

Many things might be faid, and -Gf/^^^-^^^^^^^^
heconneaion of this argument ; but m regard that we «n^ r^^^

•folve ic infew words I will ^^^^f^c Au^h

pie in animals , there are produced divers ^^^^^'^lllr rttl
the prcfent my anfwer fliall be, that in the fame manner the Earth
from one onely principle detiveth feveral operations.

Simp. But this anfwer will not at all fatisfie the Author J«

A fimfle tody
as the Earthn, can'
not move wtth
three [ever al moti-
ons*

The Edrth cdn^
Met mov: rtith any
of themotufnsaffi'
gneditl^yCopcxm'

AnfvosTS ta the
argumems contra-
ry t9 the Earths
tnotion , taken
rcrum nacura.

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2°K.B. 9,163

A fourth iAx*
tome a^Ainjt the
nt'otionofthsEdrth

Flexures necef-
far J in Mnim^lsfor
the diver Jity of
their motions.

^nether Argu-
ment Agaih^ the
threefoldmotion of
the Edrth^

G. G

AL I L^US

his Syfli

erne.

The Tlexures in
animals are not
made for the di-
ver fity of morions.

The motions of
Animals are of one
fort.

The ends rf the
lonfi Are aU ro-
tund.

h if demonf^ra-
ted^ that the ends
cf thf If ones are of
neceffitj to h to-
trtnd.

makes the ob;eflion, yea, it is totally overthrown by that which
immediately after he addeth for a greater confirmation of his argu-
ment, as you fliall hear. He re-inforceth his argument, I fay, with
another Axrome, which is this j That fiatnra in rebus neceffariis
nec chjiciat^ nec abundat : i.e. That nature in things ncceflary is
neither defefiive, nor fuperfluous. This is obvious to the obfer-
vers of natural things, and chiefly of animals, in which, becaufe
they are to move with many motion?. Nature hath made many
flexures? and hath thereunto commodioufly knitted the parts for
motion , as to the knees, to the hips, for the inabhng of living
creatures to go, and run at their pleafure. Moreover in man he
hath framed many flexions, and pynts, in the elbow, and hand, to
enable them to perform many motions. From thefe things the ar-
gument is taken againft the threefold motion of the Earth. [£/'
therthe Body., that is oHe^ and contitiuatc^ rpithont any manner of
knittings or flexion s.^ can excrcife di'vers motions^ or cannot : If tt
canwithont thetfty then in ^vain hath natute framed the flexures in
animals , which is contrary to the Axiome : but if it cannot with'
OHtthemy then the Earthy one body^ andcontinuatey and deprived of
flexnreSy and joyntSj cannot of its own nature move with plurali'
ty of motions."^ You fee now how craftily he falls upon your aH'
fwer, as if he had forcfeen it.

S A L V. Are you ferious, or do you jeft ?

Simp. I fpeak it with thebcft judgment I have.

Salv. You muft therefore fee that you have as fortunate aft
hand in defending the reply of this Philofopher, againft fome o-
ther rejoynders made to himj therefore aufwer for him, I pray
you, feeing we cannot have him here. You firft admit it for true,
that Nature hath made the joynts, flexures, and knuckles of li'
ving creatures, to the intent that they might move with fnndf/
and divers motions; and I deny this propofition h 2nd fay, that
thefe flexions are made, that the animal may move one, or more
of its parts, the reft remaining immoved : and I fay, that as to the
fpccics and differences of motions thofe are of one kind alone, t^
vi^it, all circular, and for this caufe you fee all the ends of the m^'
veable bones to be convex or concave, and of thefe fome are fph^'
rical, as are thofe that arc to move every way, as in the fliouldef
Joynt, the arme of the Enfignc doth, in difplaying the GoloU^^'
and that of the Falconer in bringing his Hawk to the lure h
^uch is the flexure of the elbow, upon which the hand turns roun^'
in boring with an augure : others arc circular onely one way,
as it Were cylindrical, which ferve for the members that bend on^'
!y in one fafhJon, as the joynts of the fingers one above another?
&c. But without more particular induftions, one only general
coiirfc may make this truth underftood ; and this is, that of a f^'^^

body

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2°K.B. 9,163

I A LOGUE,

body that moveth, one of its extreams ftanding ftill without chan-
ching place, the motion muft needs be circular, and no other : and
becaule in the living creatures moving, one of its member? doth
not feparate from the other its conterminal? therefore that motion
is of necefllty circular.

Simp. How can this be ? For 1 lee the animal move with an
hundred motions that are not circular, and very different ftom one
another, as to run, to skip, to climbe, to defcend, to fwim, and
many others.

Sa lv. Tiswell: but thefe are fecondary motions, depending
on the preceding motions of the joynts and flexures. Upon the
plying of the legs to the knees, and the thighs to the hips, which
are Circular motions of the parts, is produced, as confequents, the
skip, or running, which are motions of the whole body , and thefe
ittay poffibly not be circular. Now bccaufe one part of the ter-
reftrial Globe is not required to move upon another part immove-
able, but that the motion is to bepf ^he whole body, there is no
J^eed in it of flexures. i h.

Si m p. This (fwill the aduerfary rejoyn ) might be, if the moti-
on were but one alone, but they being three, and thofe very dif-
ferent from each other, it is not poflible that they fliould concur in

^ articulate body.

Salv. 1 verily believe that this would be the anfwer of the
Philofophcr. Againft which I mak^ oppofition another way , and
^4 you, whether you think that by way of joynts and flexures one
^ay adapt the terreflrial Globe to the participation of three difFe-
J^^nt circular motions ? Do you not anfwer me ? Seeing you arc
^Pecchleffe, I will undertake to anfwcr for the Philofopher , who
^pn\d abfglutely reply that they might , for that othcrwife it
^Puld have.focen fuperfluous, and befides the purpofe toj^aye pro.-
P^fed to coafideration, that nature maketh the flexiofl^s, to the
^Rd> the moveable may move with different motions j and that
^Wfore the terreftrial Globe having no flexures, it cannot have
^^fc three motions which are afcribed to it. For if he had
*^»^ght, that neither by help of flex|ires,it could be rendered apt
WMch motions, he would have freely affirmed, that ^be Globe
-^^^uldinot move with three motions. Jslow granting this , I intreat
and by you, if it were ppffible, that Philofopher , Au-
%rof the Argument, to be fo courteous as to teach me in what
^nv^Y thofe flexures (hould be accommodated , fo that thofe
r motions might commodioufly be excercife4 h and I grant you
e?h^ "loneths time to think of an anfw^r. As to me, it feem-
ih T pnnciple onely may caufe a plurality of motions in

^fieTerreftiiai Globe, )uft in the faanc manner that, as I told you
^ ^^e, one onely principle with itbe help of various inftruments

G g pro-

The mot tor: of
animals arc a It
circnUr,

Secondary moti-
ons of ammals de-
^CKcient oathe firji

Thi Terreftriall
Globe hnntb noe
need of flexures.

* Without joynts

It is defired to
k»ow^ bjmeAAS of
what flexures and
joynts the Terre-
ftrial Globe mioht
move with thrst
divsrfe mot ion r.

O^e only frinci-
fie may caufe a
plurality of moti-
ons in the Emh.

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2°K.B. 9,163

i54

G. G A L I L ^ u s ^ his Syjleme.

produceth fiindry and divers motions in living creatures. And as
to the flexures there is no need of them , the motions being of the
whole , and not of fome particular parts j * and becaufe they are
to be circular , the meer fpherical figure is the moft perfefi: articu-
lation or fleftion that can be defired.

Simp. The moft that ought to be granted upon this, would be,
that it may hold true in one Tingle motion , but in three different
motions , in my opinion , and that of the Author , it is impoffi-
ble ^ as he going on , profecuting the ob)e£tion , writes in the fol-
lowing words. Let us fuppofe^ wtth Copernicus, that the Earth
fno<veth of its own faculty ^ and upon an tntrtnfick, principle frorff
IVeji to Eaji in the plane of the Ecliptcl^-^ and again , that it alf<^
by an intrinftck^ principle re^ol<veth about its centre , from EaJi
IVeji ^ and for a third motion , tljtit it of its own inclination dep'
6ieth from North to South ^ and fo back^again» It being a conti-
nuate body , and not knit together with joints and fleftions , our
fancy and our judgment will never be able to comprehend, that
one and the fame natural and indiftinfi: principle , that is , that
one and the fame propenfion , fhould actuate it at the fame inftan^
with different , and as it were of contrary motions. I cannot b^'
lieve that any one would fay fuch a thing , unleffe he had undet'
took to maintain this pofition right or wrong.

S A L V. Stay a little ^ and find me out this place in the Boot
Fingamus modo cum CopernicOy teri'am aliqua fua «z//, d> ab indite
principio impelli ab Occafu ad Ortum in Ecliptic <:e piano ^ turn r^'"'
fus re^vol^/i ab indito etiam principio J circa fuimet centrum j
OrtH in Occafnnt \ tertio dejleSii rurfus fuopte nutn a fept^^*

the opfofer pf trioHe in Anfirum\ viciffim. I had thought , Simplicif^
Coptrnicv-s. m^t have erred in reciting the words of the

thor 5 but now I fee that he , and that very grdifcly , dec^'
vethhimfelf^ and to my grief, I find that he hath fet himfelf^
oppofe a pofition , which he hath not well underftood \ for th^^^
are not the motions which Copernicus aflignes to the Earth'
Where doth he find that Copernicus maketh the annual moti^^^
by the Ecliptick contrary to the motion about its own centre ?
muft needs be that he never read his Book , which in an hundf^
places, and in the very firft Chapters affirmerh thofe motions^
be both towards the fame parts, that is from Weft to E^*^
But without others telling him , ought he not of himfelf to co^^
prehend , that attributing to the Earth the motions that are ta^
l^^n , one of them from the Sun , and the other from thei^'"^'
ntum uiehile ^ they muft of neceffity both move one and the f^^^
way.' -

^ f'Mii and S^i^ P. Take heed that you do not erre your felf , and (^^Pf^^
v^nh^i jimpie 4r- ^HS alfo. Thc Diumal motion of the prmmn mobile^ is it notff^^

Copernicus.

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2°K.B. 9,163

Dialogue

Eaft CO Weft > And the annual motion of the Sun through the
EcUpcick, isit not on the contrary from Weft to Eaft ? How
then can you make thefe motions being conferred on the Larth, ot
contraries to become confiftents ? . • • i

Sagr. Certainly, SmpUciits hathdifcovercdto us the onginal
caufe of error of this Philofopher i and in all probabihty he
would have faid the very fame. .

S A L V. Now if it be in our power , let us at leaft recover
Smplicim from this errour , who feeing the Stars ,n their n(mg
to appear above thd Oriental Horizon, will make it no difficult
thing to underftand , that in cafe that motion Ihould not belong
to the Stars , it would be ncccflary to confeffe, that the Horizon,
with a contrary motion would go down i and that confequently
the Earth would reooUe in it felf a contrary way to that where-
with the Stars feem to move, that is from Weft to Eaft , which
is according to the order of the Signes of the Zodiack. As, in the
next place! to the other motion, the Sun being fixed m the cen-
tre of the Zodiack , and the Earth moveable about 'ts^tcumte-
rence to make the Sun feem unto us to move about the laid Zo-
dia k' accord ng to the order of theS.gnes, it is neceffary , that
th E ^rth move Lording to the fame order , to the th« the
Sun may feem to us to pofTelTe alwayes that degree in the Zodiack,
that is oppofitc to the degree in which we find the Earth ; and thus
the Earth running, mrbi gratia, through ^m. the Sun will
appear to runthorow Lzbra; and the Earth paffing thorow the
figne Tanrm , the Sun will palTe thorow Scorpio, and lo the
Earth going thorow Gemini, the Sun feemeth to go thorow S^-
gittartHs i but this is moving both the fame way , that is accord-
ing to the order of the figncs •, as alfo was the revolution of the

't:^[t"y:uverywell, and know not what toal-
'1:rTndyt[i&

iti^iai^etCthelarth move by the diurnal motion abou^^
its own centre from Eaft to Weft i and perceives /"J'^J*
vverefo, the motion of twenty four hours W";*;'*^^^™
»o theUniverfe , would, in our fecmmg, proceed from WcU to
Eaft -, the quite contrary to that which we behold.

Si MP. ^hftrange! Why I , that have fcar<^fcent^^^^^^^^^^
jWnts of the Sphere, would not, I am confident, have erred

''sTf'v!'"]ud« now what pains this Antagonift may be thought
tohavetakin in tL Books of CofcrnU^ , if heabfolutely inve
?efenfeof this grand and p.incipal Hypothefis , upon which ,s
founded the whole fumme of thofe things wherem Coff"^"^

'35

The crrcr of the
Antagonifi is md'
mfefl , hy decla-
ring that the an"
rttAl and. dtnrnal
rnothns belonging
to the FArth *re
hoth oney^Aj ,^ Mfid
not cor.trnrj.

Bjitnotl ergrop .
error tt U feen that
theyJ»tagOftifi had
hfii Utile ftudied

Copernicus.

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2°K.B. 9,163

z}6

I: if tjue/ItsiKfJy
nhfiLer the cppo-
Kfnt HXiierfiood
the third motion
a}Jjgnci to tie
f/«r//;^/ Coperni-
cus.

again?

The fame *tr^u-
mevt anfxverei hy
examples of the
iike motfffr.s in o-
ther coelejtial bj^
dies.

G A L I L /E u his Sy^cmcj.

diffenteih from the doctiiiic of Arijlotlc and Ftolomy. As
to this thhd motion, which the Author aillgnes to the Terreftrial
Globe, as the judgment of Coper nt cm ^ I know ifot which he would
mean thereby : it is not that qiicftionleiH-, which Copenium af-
cribes unto it conjunftly with the other two, annual and diurnal,
which hath nothing to do with declinmg t9wards the South and
North ^ but onely ^erveth to keep the axis of the diurnal revoluti-
on continually parallel to ic fell , fo that ic mull be confeft, that
either the Authour did not underftand this, or that elfc he dilfcm-
bled it. But although this great miftake fufRceth to free us from
any obligation of a farther enquiry into his objeQionss yet ne-
vcrthelcife I (hall have them in eftcem ^ as indeed they deferve to
be valued much before the many others of impertinent Antago-
nifts. R e turning therefore to his objefii^n, 1 fay, that the two
motions, animal and diurnal, are not in the leaft contrary, nay are
towards the fame way . and cherefore may depend on one and the
fame principle.The third is of it felf,and voluntarily fo confequcii-
tial to the annual, that we need not trouble our felves (fas I fliall
(hew in its place) to ftudy for principles either internal or externalj
from which, as from its caufc, to make it produced.

S A G R. 1 (hall alio, as being induced thereto by natural reafon?
fay fomething to this Antagonift. He will condemn CopernzcuS)
unlefTe i be able to anfwer him to all objeftions, and to fatisfie
him in ail queftions he (hall ask ^ as if my ignorance were a necef-
fary argument of the fal(hood of his Doftrine. But if this way of
coi demnH.g VVrite^^^ j ,^ .

think It unrcalonable, if I fliould not approve of Ariftotle and f
lomy, when he cannot rcfolve, better than my felf, thofe doubts
which I propound to him, touching their Doftrine. He asketh iiK,
what arc the principles by which the Terreftrial Globe is moved
with the Annual motion through the Zodiack, and with the Diur-
nal through the Equinofiial about its own axis. I anfwer, that
they ate like to thofe by which ^S'^/wrw is moved about the Zodi-
ack in thirty years, and about its own centre in a much fliortcr
time along the Equinodial, as the collateral apparition and oc-
cultation of its Globes doth evince. They are principles like t^
thofc, whereby he fcrupleth not to grant, that the Sun runneth tho^
row the EcJiptick in a year, and revolveth about its own ccntt^
parallel to the Equinoftial in lefFe than a moneth, as its fpotsdoth
■^enfibly demonftratc. They are things like to thofe whereby the
^edicean Stars run through the Zodiack in twelve years, an^^
all the while revolve in fmall circles, and (hort periods of time
bout Jnp^ter,

S i m p. This Author will deny all thefe things, as delu(ions oi
the light, caufed by the cryftals of the Tele/cope.

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2°K.B. 9,163

I ALOGUE.

II.

-37

S A G R. But this would be to draw a further inconvenience up-
on himfelf, in that he holdeth, that the bare eye cannot be decei-
ved in judging of the right motion of dcfcending graves, and yet
holds that it is deceived in beholding thefe other motions at fuch
time as its vifive vertue is perfeSed, and augmented to thirty times
as much as it v^as before. We tell him therefore, that the Earth in
like manner partaketh of the plurality of motions: and it is per-
haps the fame, whereby the Loadftone hath its motion down-
wards, as grave, and two circular motions, one Horizontal, and the
other Vertical under the Meridian. But what more , tell me, Sim-
plicim^ between which do you think this Author would put a
greater difference, 'cwixt right and circular motion, or 'twixt moti-
on and reft ?

Simp. 'Twixt motion and reft, certainly. And this is mani-
**^ft5 for that circular motion is not contrary to the right, according

AriUotls nay, h * granteth that they may mix with each o-
ther ^ which it is impoffible for motion and reft to do.

Sagp. Therefore its a proportion lefle improbable to place
in one natural body two internal principles, one to right motion,
^nd tJic other to circular, than two fuch interne principles one to
Motion, and the other to reft. Now both thefe pofitions agree to
the natural inclination that refideth in the parts of the Earth to re-
turn to their whole, when by violence they are divided from it y
ind they onely diffent in the operation of the whole : for the lat-
ter of 4:hem will have it by an interne principle to ftand ftill, and
theformerafcribeth to it the circular motion. But by your con-
ceflion, and the confeflion of this Philofopher, two principles, one
to motbn, and the other to reft, are incompatible together, like as
tneir efFefts are incompatible : but now this cvenes not in the two
lotions, right, and circular, which have no repugnance to each
^ther.

S A L V. Addc this more, that in all probability it may be that
motion, that the part of the Earth fepatated doth make whilft
^^J'^turneth towards its whole, is alfo circular, as hath been alrea-
dy declared ^ fo that in all refpefts, as far as concerncs the prefcnt
^^f^i Mobility feemeth more likely than Reft. Now proceed,
^^plicius^ to what remains.
S 1 M p. The Authour backs his Argument with producing ano-
^ner abfurdity, that is, that the fame motions agree to Natures ex-
^^^atnly different ^ but experience flicweth, that the operations
Motions of different natures, arc different and Reafon con-

Motion and rejh
ars more different
thitn right motion
and circftUr*

One mmj more
rationally afcrile
to the S4Tth twy
tnternal prtKciplef
to the right , and
circular mctiorj >
thantrvo to motion
4nd refi*

The motion of
the parts of the
£arth returning to
their whole may irs
circfilar.

firmeth

the fame : for otherwife we (hould have no way left to

The dtverfny of
motions helpeth U4

^ in kjiowin^ thedt'

•^now and diftinguifli of natures, if they ftiould not have their verftyof hmhtcs.
particular motions and operations, that might guide us to the
*^nowledgcof their fubftances.

S A G R»

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

25S

Nature J?r/?
madethi^gt^ i^'
pleafed, W after-
wards capacitated
mens under ft and-
tKgsfcr cor.ceiving
ef thtm.

Copernicus er-
rene»ujly nfigneth
the fame operations
to different natures

Tr6m eommupie
dccidents one catt^
not kl^ow different
natttres.

G. Galil^us, his Sjfleme.

S AG K. 1 have twice or thrice obferved in the dircourlcs of this
Authoiir, that to prove that a thing is fo, or fo, he ftill alledgeth)
that in that manner.lt is conformable with our underftanding ? ot
that otherwifc we (hould never be able to conceive of it ^ or that
the Criterinm of Philofophy would be overthrown. As if that na-
ture had firft made mens brains, and then difpofcd all things it^
conformity to the capacity of their intelUfts. But 1 incline rather
to think that Nature firft made the things themfelvcs, as (he beft
liked, and afterwards framed the reafon of men capable of con-
ceiving (though not wijiout great pains^ fome part of her fe-
crets.

S A L V. I am of the fame opinion. But tell me, SimpliciJ^'>
which are thefe different natures , to which, contrary to expc'
ricnce and reafon, Gopernicu^ ^Signes the fame motions and opc
rations.

Simp. They are thefe. The Water, the Air, (which doubt-
leffe are Natures ditfercnt from the Earthj and all things that
are in thofc elements comprifed, fhall each of them have thoft
three motions, which Copernicus pretends to be in the Terreftriall
Globe and my Authour proceedeth to demonftrate Geomctfi"
cally, that, according to the Cop er«/c^« Doftrine, a cloud that
fufpended in the Air, and that hangeth a long time over oUf
heads without changing place, muft of neceflity have all thofe thre^
motions that belong to the Terreftrial Globe. The demonftr^^'
rion is this, which you may read your felf, for I cannot repeat
without book.

S A L V. I fliall not ftand reading of it, nay I think it an impef"
tinency in him to have inferted it , for I am certain that
Copernican will deny the fame. Therefore admitting him what
would demonftrate, let us fpeak to the objeSion, which in my
judgment hath no great ftrcngth to conclude any thing contrary
to the Copernican Hypothefis^ feeing that it derogates nothing fr^^^
thofe motions, and thofe operations, whereby we come to th^
knowledge of the natures, &c. Anfwcr me, I pray you, SimpH^^'
m : Thofe accidents wherein fome things exaftly concur ,
they ferve to inform us of the different natures of thofe things ^

Simp. No Sir ; nay rather the contrary, for from the idendi^y
of operations and of accidents nothing can be inferred, but
idcndity of natures.

S A L v. So that the different natures of the Water, Earth? A^^^
^nd other things conteined in thefe Elements, is not by youarg»i'
ed frotn thofc operations, wherein all thefe Elements and their ar
fixes agree, but from other operations ^ is it fo >

S 1 M p . The very fame.

Sa l v. So that he who fliould leave in the Elements all tW^

motion^'

Dialogue II. ^39

J ►i.^r arrlflpnts bv which their natures
motions, operations, and other accidents, ^> ^ ■

are diftinguifhed, would not deprive us oU^'Xc^""^ Zk o-
to the knowledge of them i although he f^^^'f.^.^'r.'J
perations, in wh.ch they unitedly concur, ar.d vvbch to. that reato«
are of no ule for the diftinguifhing of thole natures^
S 1 M f I think vour dillertation to be very good.

; But haLheEarth,Water,A.r, areot a nature equally
conmtuted hloveable about the centre, not the op.n.on of
your felf, AnfloHc, P^olomy, and all the.r ^f^^^ ^
S I M V. Its in all hands granted as an ""^^.^"'^^^^ "7^f
S . L V. Then from this common natural '^^^'^Jl ye/elt
cence about the centre, there is no argument drawn o^ the d.fteren
natures of thele Elements , and things ^1^™^"";^ '^^^^^^^^^^^^^
knowledge muft be coUeaed from <>[»^"^,q"^^";:%"^4;~n
and therffore whofo Ihould deprive f ^el ^the opem^^^
reft only, and ftiould leave unto them all their othe P ,
would not in the leaft block up the way drat l.^^j^^^^^^^^^^^
l^geof their e^ences But^V^^^^^

this common reft, and „p,,,rds, downward,,

leaving them gravity, levity, ^ ^„ .fhot, cold, dry, moift, Th> c,rcurr,u.

n ° r A-r raritVidenfity, the qualities Oinoi, J, oftheEl memm

aowcr, fafter, ranty, y^ therefore fuch an abiurdity,. as

and in a word, all things Dciiaes i CoMrnicau pofition i nor 7"

rK;c Ai.thnur imaaineth to himlelt, is no C/Open«t«» i>"i". crttfc, th-.»,h«r

this Authour imagiucui ' r motion import any more ctf .„«Krr«« » -

doth the concurrence in an laenuiy A^,,.- fV..-

lefs, than the concurrence in an identity of ^^^['^^ ^'J

fying, or not diverfifying of natures. Now tell m, if thtie any

"^^:!^m:S;haSeihobjeaW^

ralobfetvation,whichis,T^,.j W.. ./^ .,^^4
tions that igrtc in k;nde, or efe th^y J n,oft fem- BU.. cf
pern.canHyVtheGs,W|e^^^^^^ %J.Ly f^^t,^!.

hlahU to cm another, r^ould ^^yJ'J J. ,„,ther, n>ouid .r.k,.:U.

repugnant astomotion; for that ^^""'f ^, pUnets teoMprfe-

le nelcrthelefe fo unlths ^n ntotton.f tlTsZ^^ould ^ilnd
tKallytHr^roJd; bntthcSHnandaUthcfixecdbtarsrf j

perpetually immoveable. „„^arprh ffood i but yet

The forme of the "gUment appeareth go y^^^

I believe that the application or matter is a .^^^^
Authour will but perfift in his affumption, the n

«^ake direaiy againft him- The Argument m" ,
-undaneboL^ilx there are that do perpetu^^^^^^^^ w,.

*re the fix Planets, of the r^ft' J^V'lhem moveth, and which W fi-»f
fixed S,,,, it is difputable ^bch o^^^^^^^^^

ftands am, it being neceflary, hat^t t ^^^^
and fixed Stars do move i a»d It being k- i v and '«"''"'^*

M° G. G A L r L j« u s, his Syjime.

and fixed Stars may ftand immoveable, in cafe tlie Earth fliould
move : the matter of fad in difptitc is, to which of them we may
with moft convenience afcribe motion, and to which reA. Natural
reafon diftates, that motion ought to be afligncd to 4he bodies,
which in kind and elTence moft agree with thole bodies which do
undoubtedly move,and reft to thofe which moft Jillent from them;
and in regard that an eternal reft and perpetual motion are moft
different, it is manifeft, that the nature of the body always move-
able ought to be moft different from the body alwayes ftabk-
Therefore, in regard that we are dubious of motion and re/1,
let us enquire, whether by the help of Ibme other eminent affefti-
on, we may dilcover, which moft agreeth with the bodies certain-
ly moveable, either the Earth, or the Sun and fixed Stars. But fee
how Nature, in favour of our necefllty and dcfire, prefents us
with two eminent qualities, and no lefs different than motion and
reft and they are light and darknefs, to wit, the being by nature
moft bright, ana the being obfcure, and wholly deprived of light:
the bodies therefore adorned with an internal and eternal Iplcn-
dour, arc moft different in effence from thofe deprived of light:
The Earth is deprived of light, the Sun is moft fplendid init lelf,
and fo are the fixed Stars. The fix Planets do abfolutely
want light, as the Earthy therefore tlieir.cffenceagrceth with
the Earth, and diftereth from the Sun and fixed Stars There
fore is the Earth moveable^ immoveable the Sunne and StarrY
Sphere.

. ^wl' ^'!l?'^"'''''"'^'""°*g''^n^^f«t,thefix PW
tenebiofe, and by that negative will he abide.. Or he will argttC
the great conformity of nature bqtween the. fix Planets and W
|un, and F.xed Stars, and the dUpar,ity fah^een S.^^ tl
tarth trom other conditions than from tcncbrcxfity and light • yet,
now I remember in the fifth obje^ion, which foUowcth, ,he layetji
down the vaft diffciencc between the Earth and the Coelefti^^
JJS'ftT: 'V^'"^ writeth T&.^ the Copernican Hypothefis

pcrn.cus. .J^oM maks grf^t confHfiott aftd perturbatiau m tbe Syfteme of the

, "y^l^^rfyndamongtiitspa^ts -. As for .inftance, amongft GoJ-
^.^'^^^f '.^"^ immutable and incorruptible, according Ar.^'
Eanh,.d.h,c«. «*5 T^ychv, and others i amongft bodies, I fay, of fud, nobility, by
uil.dioiic,, ,4. the confeffion of every one, and Cofermcns himfelf, whro affirmed
S{:;r"'" ^^-^ to be ordinate, and difpofed in a p^rfeft cont^don a^d
temoveth from them all inconftantjy of vertue amongft thcfe bo-
^s, I fay once more, fo pure,that is to fay, amongft Fe««^, Mars,
^^•_to place the very fink of all corruptible matters, to wit, the
tanh, Avatcr, Air, and all mixt bodies. . .

ve2 wLk nnichpropcrer a diftribution, and more, with nature,
yea with Godhimlclf, the Architta, is it, to fcqueftcr the ^

from

Dialogue. IIv

fi'om theimpure the mortal from the immortal , as other Schools
teach, which tell us that thele impure and frail matters are con-
tcincd within the anguft concave of the Lunar Orb, above which
^vith uninterrupted Series the things Celcftial diftend themfclves.

Salv. lt*s true that the Copernican Syfteme introduceth di-
ftraSion in the univerfe of Aristotle ^ but we fpcak of our owit
Univcrlc, that is true and real. Again if this Author will infer
thedifparity of cflence between the Earth and Celeftial bodies
fiom the incorruptibility of them 5 and the corruptibility of it in
the method of Arifiotle ^ from which difparity he concludeth mo-
tion to belong to the Sun and fixed Stars, and the immobility of
^ Earth , he will flatter himfelf with a Paralogifme , fuppofing
t lat which is in queftion i for Arijiotle inferreth the incorruptibi-
of Celeftial bodies from motion , which is in difpute , whe-
^^er it bclongeth to them or to the Earth. Of the vanity of thefc
*^hctorical Illations enough hath beenfpoken. And what can be
j^ore fond , than to fay , that the Earth and Elements are bani-
ihed and fequcftred from the Celeftial Spheres , and confined
within the Lunar Orb > Is, not then the Moons Orb one of the
Celeftial Spheres , and according to confent comprifed in the
middle of all the reft ? Its a new way to feparate the pure front
4e impure , and the fick from the found ^ to afligrie the infe£tcd
quarters in the heart of the City : I had thought that the " Pcft-
Sbufe ought to have been removed as far off as w^s poflible.
^opernicus admireth the difpofition of the parts of the Univerfe ,
l^r that God hath conftituted the grand Lamp, which is to give
^ght all over his Temple in the centre of it , and not on one
^^c. And as to the Earths being betwixt Venus and Mars^
^ve will but hint the fame j and do you, in favour of thi^ Author,
pj^ to remove it thence. But let us not * mix thefe Khetoiical
lowers with folid Demonftrations y rather let us leave them to
J^e Orators , or if you will to the Poets , who know how in their
j/olling way to exalt by their prayfes things rhoft fordid , yea and
^^JJ^etimcs nioft pernicious. And if any thing elfe remain j let us
^'P^tch it, as we have done the reft.

^ ^iMp. There is the fixth and laft argument , wherein he ma-
^^yUt a very improbalc thing. [That a corruptible and dtppahle
he^ ^i^*^^^^ ^^^ove -with a perpetual and regular motion , and this
^I^^^^^^P^^^eib wah the cxampU of lining creatures^ which moving
ret \^ '^^^^^'^ natural to them , yet groxp weary^ and ha^e need of
wkh ^^fi^^^ '^^^^^ yfre/;^//^.] But what hath this motion to do
BefidV^ the Earth ', that in comparifon to theirs isimnicnfe ?
fev ^^^'^^ "^^^^ ^^^'^ ^'^^^^ motions that run and draw

h^r^J^^^yes: Who would ever affert futh Paradoxes , unlcffe
Iworn to be their defender ? Nor doth that avail in this

H h cafe.

Copernicus itT
troducnh confujiom
in the Univerft of
Arittotlc.

The Paralogifme
cf the j^mhor of
Ami' Tjcho,

ft [eemeth a
folly to affirm the
F.itrth to hewtth-
oHt the Heivens,

^ * l-ntrecc 'tAfi-i
t'vVinc flowers m a
garland.

€^ ftxth Ar£U»
nnnt agatnfi Co-
pern Jcui > taken.

have need of refi '^
though tbetr moti-
on be natHr^l'

An Argumm
from K'.'pler tn fa-
Vi^ftr of Coperni-
cus.

77jg Jtith»r »f
^r/Jrf^ Kepler.

Th vehcitj of
the circular mott-
ttincrrfiftth^ ac-
corAin^ to the eft'
creafe of the diX"
meter af the vircie.

G. G All L JEUS J his Syjleme:

cafe, which Copernicus alledgeth, that by reafoii this motion is
natural to ihe Earth and not violent, it workcth contrary tfFcctii
to violent motions , and that thofe things dilTolve and cannot
longiublift , to which impulfe is conferred , butthofc lo made
by nature do continue in their perfefi difpoture *, this anfwcr fuf-
ficeth not, I lay , for it is overthrown by that of ours. For the a*
nimal is a natural body 5 and not made by art, audits motion is
nauiral , deriving it ieU from the foul , that is, from an intrinfick
paaciple , and that motion is violent , whofe beginning is with-
out , and on which the thing moved conferreth nothing ^ how-
ever, if the animal contbueth its motion any long time , it groWS
weary , and a!fo dyeth, if it obftinately ftrive to perllft therein.
You fee then that in nature we meet on all li'des with notions con-
trary to the Copcrnican Hypothefes , and none in favour of it. Ari
foi that I have nothing more wherein to take the part of this Op-
pone iit , hear what he produceth agalnft Kcplerm (with whom
hedifputeth) upon that argument, which chefaid Kepler bii;»gcrb
againft thofe who think it an inconvenient , nay impofuble thing)
to augment the Starry Sphere immenfely 5 as the topcmicanbly^
pothelis requireth. A^p/^r therefore inftanceth, faying : Dtfficili'
HseH^ accidens prater modnlum fubjeHi intcndere quam fiA'
jeciitnt fine accid^ntc angere. Copernicus ergo <verijimilius facit,
qui anget Orbem Stellar nm fixarnm abjque motn , quam Ftolom^/^^^
qui auget inoturn jixarnm immenja 'ueiycitate. [Which makes thi^'
Englilh.^Its harder to firetch the accident beyond the model of th^
fubjed than to augment the fubjeft without the accident. Coperni'
hach more prob bility on his fide , who encreafeth the Orb of th^
fixed Scars without motion , than Ftolomy who augmenteth tb^^
motion of the fixed Stars, to an immcnfe degree" of velocity-
Which objedion the Author anfvvereth , wondering how much
Ke^/er deceived himfeJfjin i'aying,that in the PiOiomaick Hypoth^^'
fis the motion cncreafeth beyond the model of the fub) jft , for ii*
his judgment it doth not encrcafe, fave onely in conformity toch^^;
modjl, and that according to its encreafemcnt , the velocity^''
the motion is augmented. Which he pro vet h by fuppofinga m^'
chine to be framed, that maketh one revolution in twCiity fi>^^^
hours , which motion /hall be called moft flow 5 afterwards fi^P'
poflngits femidiameter to be prolonged, asfarasto the dift^^^^^
of the Sim , its extreme will equal the velocity of the Sun ;
it bei?'gcantinued out unto the Starry Sphere, it will equal
velociry of the fixed Stars, though in the circumferrnce o[^^^
machine it be very flow. Now applying this confideration oi ^'^^
machine to the Starry Sphere , let us imaaine any point in its
midiametcr , as neer to the centre as is the iemidiameter of the iti^'
chme ; the IV^e motion that in the Starry Sphere is exce^^!^'^

D I A tOG UE. II.

24)

An explanation

of the true fen(eof
Kepler and hUde-
fence.

iwifc , fliall in that point be exceeding flow But the great mag-
nitude of the body is that which makech it of exceeding (low , to
become exceeding fwift , although it continueth ftill the fame, and
thus the velocity encreafcth , not beyond the model of the fub-
jeft , but rather according to it , and to its magnitude , very dit-
ferentlyfrom the imagination of Kepler^

S A L v. 1 do not beheve that this Author hath entertained fo
mean and poor a conceit of Kepler ^ as to pcrf wade him felf that
he did not underftand, that the higheft term of a line drawn from
the centre unro the Starry Sphere , moveth more fwiftly than a
point of the fame»line taken within a yard or two of the centre. And
therefore of neceffity he muft have conceived and comprehend-
ed that the mind and intention of Kepler was to have faid, that
It is lefTc inconvenient to encreafe an immoveable body to art ex-
traordinary magnitude , than to afcribe an extraordinary velocity
to a body , though very bigge , having regard to the model ,
fhat is to the gauge , and to the example of other natural bodies^
i« which we fee, that the diftance from the centre encreafing , the
Velocity diminiQiethi that is, that the periods of their circulati-
ons take up longer times. But in reft which is not capable af aug-
mentation or diminution , the grandure or fmalneffe of the body
niaketh no difFcreuce. So that if the anfwer of the Author would
be dircded againft the argument of fCef fer , it is nece^fary , that
that Author doth hold, that to the movent principle its one and the
fame to move in the fame time a body very fmall , or very im-
iiaenfe , in regard that the augmentation of velodty infcparably
attends the aufirmentation of the maffe. But this again is contrary
to the Architeftonical rale of nature , which doth in the lelTer
Spheres y as we fee in the Planets r a?nd moft fenfibly in the Medi-
cean Stars , obferve to make the leffcr Orbs to circulate in Sorter f'^^'s. andthchi'
times : Whence the time of Saturn^ revolution is longer than all
^fc^ times of the other leffer Spheres , it being thirty years ; now
fbe pafling from this to a Sphere very much bigger , and to make
^^naovc in a 4. hours , may very well be faid ta exceed the rules of
^f^e model. So that if we would biit attenttvely confKlerit, the
^^thors anfwer oppofeth not the intcftt and fenfe of the argument,
^ the expreffi^ and manner of delivering of it i whc^'e again
Author is injurious , and cannott deny but that he arttfittally
^iffembledhis underftanding of the words, that he might charge
'^r with groife ignorance but the impofture Was fo very dull
*«^c4)vions, that he could not withal! his craft alter theopini-
which Kep/er hath begot of his Dodrine in the minds of all
Learned As in the next place , to the inftance againft the
P^^P^tual motion of theEartk, taken from the impoffibility of
Jts^ movitig long withouc wearineffe , m regard that living crea-

H h 2 turcs

Th€ greatnejfe
And ffH0tlnejfe af
the body tnak^ ^
dtference tn woti^
on and not in reft.

The order of n*'
tyre^tonsake the
Itffer Orbs to cir-
tul^te in fhorter

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

244

7hf feigned an-
fwer of Yiiplcx CO'
vered rvith an ar-
tificial Iron].

tAKtmaU vfould
not grow vpeary of
the%r motian-f pro-
ceeding as that
rvhich is ti/pgfted
to the terreftrial
giob'e.

The caufe of the
roearineffe of ani-
mah.

The motion of
an dmmdl is rathtr
to be called violent
than natural.

the flrength di-
Wtnifheth not^
where it is ntt im-
plojtd.

G. G hLiL^uSy hu Syfleme.

tures thcmfelvcs 3 which yet move naturally, and from an intern
principle, do grow weary, and have need of reft to relax and re-
frefli their members

S A G R. Methinks I hear Kepler anfwer him to that , that
there are fome kinde of animals which refrefti themfclves after
wcarineffe, by rowling on the Earth , and that therefore there
IS no need to fear that the Terreftrial Globe (hould tire, nay it
may be reafonably affirmed, that it cnjoyeth a perpetual & moft
tranquil repofe, keeping it felf in an eternal rowling.

S A L V. You are too tart and Satyrical, Sagredm : but let us
lay afide jefts, whilft we are treating of ferious uhings.

S A G R. Excufe me, Sal*z/iatf^^ this that I fay is not fo abfo-
lutely befides the bufinefs, as you perhaps make iti for a motion
that ferycthinftead of reft, and removeth wearinefs from a body
tired with travail, may much more eafily ferve to prevent the cO'
mingof that wearinefs, like as preventive remedies are more eafic
than curative. And I hold for certain, that if the motion of ani-
mals (hould proceed in the fame manner as this that is afcribed to
the Earth, they would never grow weary , Seeing that the weari'
nefs of the living creature , deriveth it felf, in my opinion, from
the imployment of but one part alone in the moving of its fctf>
and all the reft of the body j as *z/. g> in walking, the thighs an<J
the legs onely are imployed for carrying themfelves and all the
reft ; on the contrary, you fee the motion of the heart to be as
were indefatigable, becaufe it moveth it felf alone. Befides, I
know not how true it may be, that the motion of the animal is na-
tural, and not rather violent : nay, 1 believe that one may truly
fay, that the foal naturally moveth the members of an animal with
a motion preternatural, for if, the motion upwards is prcternatU'
ral to grave bodies, the lifting up of the legs, and the thighs?
which arc grave bodies, in walking, cannot be done without \i(y
Icnce, and therefore not without labour to the mover. The
climbing upwards by a ladder carrieth the grave body contrary
its natural inclination upwards, from whence followeth wearinefs,
byreafonof the bodies natural aver fnefs to that motion: but in
moving a moveable with a motion, to which it hath no avcrfion?
what laffitude, what diminution of vertue and flrength need v^e
fear in the mover ? and how (hould the forces wafte, where the/
are not at all imployed ?

S I M p. They are the contrary motions wherewith the Earth is
pretended to move, againft which the Authour produceth his ar-
g^^ent.

^ A It hath been faid already , that they are no wife con-
traries,, and that herein the Authour is extteamly deceived,
that the whole ftrength of the argument recoil eth upon the Op-

potnent

Dialogue. II.

Z45

ponent himfelf, wliilft he will make the Firji Moz^er to hurry
along with it all the inferiour Sphere?, contrary to the motioa
^vhich they themfelvcs at the lame time exercife. It belongs there-
fore to the Frimiun Uobtle to grow weary, which b^nides the
moving of itsfelf is made to carry fo many other Spheres, and
which alfo ftrive againft it with a contrary motion. So that
the ultimate conclufion that the Authour inferred, faying, that
difcourfing of the ej[Fe& of Nature, a man alwayes meets with
things that favour the opinion of Artftotle and Ptolomy, and ne-
ver any one that doth not intcrfer with Coperfitcns^ii^nds in need
of great coniideration h and it is better to fay, that one of thefe
two Hypothcfcs being true, and the other neceffarily falfe, it is
impoffibic that a man fliould ever be able to finde any argu-^
T"^^nt^ experience, or right rcalbn, in favour of that which is
falfe, like. as to the truth none of thefe things can be repugnant.
Vaft difference, therefore, muft needs be found between the rea-
fons and arauments produced by the one and other party, for and
againft thclc two opinions, the force of which 1 leave you y out
felf to judac o{, Smplicius, r - / ' '> "'^

S A L V But you, Sagredus, being tranfported by the velocify^^
of your wit, have taken my words out of my mouth, whilft I wa^
about tofayVomething, touching this laft argument of the Author-^
and although you have more then fufficiently refuted him, yct^
Oeverthelefl'e 1 will adde fomewhat, which then ran in my minde.-
He propofeth it as a thing very unlikely ^ that a body diflipable
and corruptible, as the Earth, fhould perpetually move with a re-
gular motion, cfpecially for that we fee living creatures in the end
to grow weary, and to ftand in need of reft : and the improbability
is increafed, in that the faid motion is required to be of velocity
incomparable and immenfe, in refpeft to that of animals. Now, I
cannot fee why the velocity of the Earth fhould, at prefent, trou-
t^le it , fo long as that of the ftarry Sphere fo very much bigger
^oth not occalion in it any difturbance more confiderable,than that
^hich the velocity of a machine, that in ^4 hours maketh but one
f^Ie revolution, produceth in the fame. If the beingof the velo-
% of the Earths converfion, according to the model ot that ma-
^'^tt^e,inferreth things of no greater moment than that, let the An-
chor ceafetofear the Earths growing weary ^ for that not one ot
^he moft feeble and How-pac t ammals,no not a Ghamaeleon would
in moving no more than * four or five yards in ^ hours ^ but
Pleafe to confider the velocity to be no longer, m relation to
the model of the machine, but abfolutely, and inafmuch as the
nioveablc in 14 hours is to pafs a very great fpace, he ought to fliew
himfi^If fo ,^uch more referved in granting it to the ftarry Sphere,
Which with a velocity incomparably greater than that of the
^ Earth

of Claramonrius,
recoileth fiPonhtm-

True ProPofiti-
em meet with mA-
ni conclu.five av
^umencs, fa do not
'thefalfe.

* Cinque 6 fci
braccia Fiorcncini.

fyearine(? more
to he fedred in the
Jlarrj Sphere than
in the terrefirUU

G. G A L I L /E u s, his Syjimc.

Earth is to carry along with itathoufand bodies, each much big-
ger than the Terreftrial Globe.

Here it remains for us to fee the proofs, whereby the Authouf
concludes the new ftars Anno i 57a. and Anno 1 60^. to be fublu-.
nary, and not coeleftial, as the Astronomers of thofe times were
generally perfwaded *, an cnterpriz.* very great certainly ^ but I
have confidercd, that it will be better, in regard the Book is neW
and long, by reafon of its many calcnlationsj that between this e-
vening and to morrow morning 1 make them as plain as I can, an^l
fo meeting you again to morrow to continue our wonted conft'
rences, give you a brief of what I (hall obfcrve therein ; and if
have time left, we will fay fomething of the Annual motion aicri-
bed to the Earth. In the mean time, if cither of you, and Simfl^'
cius in particular5hath ^ny thing to fay more,touching what relates
to the Dinrnal motion., at large examined by me, we have a little
time ftill left to treat thereof. '

Simp. I have no more to fay,unle{re it he this, that the difcouf-
fes that this day have falne under our debate, have appeared to me
fraught with very acute and ingenious notions, alledged on Co^^f
nicHS his fide, in confirmation of the motion of the Earth, but ye^
I find not my felf perfwaded to believe it ; for in fliort, the things
that have been faid conclude no more but this, that the reafofl^
for the liability of the Earth are not neceffary ; but all the whil*
no demonftration hath been produced on the other fide that dock
ncGeffarily convince and prove its mobility.

S A L V. I never mii^nook.StmpliciHs, to remove you from that
your opmion i much lefs dare I prefume to determine definitively
in this controverfic : it onely was, and fiiU ftall be in the enfuing
difputations i»y mtent, to make it appear to you, that thofe wb^^
have thought that raoft fwift motion of a4 hours doth belong
the Earth alone, and not to the Univcrfc, the Earth onely excla-
dcd, were not induced to believe, that fo it might and ought to
out of any blind pesfwafion ^ but that they did very well fee, try^
and examine the reafons on the contrary fide, and alio not flight'
ly anfwcr theni. With the fame intention, if it ftand with youi*
liking, and that of Sagrcdus, we may pafTe to the confidcracion of
that other motion ^ firft, by AriUarchm Samiusy and afterwaf^^
by NnhoUm Cofernicm aferibed to the faid Terreftrial Globe?
which is, as, I believe, you have heretofore heard, made under the
Zodiack within the fpace of a year about the Sun, immovcably
placed in the centre of the jGaid Zodiack.

S I M p. The difquifition is fo great, and fo noble, that I fli^"
l^^jl^i^^earken to the difcuflion thereof, perfwading my fe If that I
ihall heat what ever can be faid of that matter. And 1 will aftct'

lib
if
th

w
a(

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2°K.B. 9,163

Dialogue

wards !>y my felf, according to tiiy ulual cuftome, make more de-
liberate reflcxioas upon whac hath been, and is to be fpokcn i and
if I fiiould gain no more but this, it will be no fmaU baneht
that I ihall be able to difcomie mare Logically.

Sagr. Therefore, that we may no further weary Salvtatm,
we will put a period to th: difputations of this day , and re-
iffame our conference to morrow in the ufual manner, with hope
tohcar very pleafing novelties. . „ „ „. • .

S I „ P. I will lea?e with you the Book DefleU>s and car-
ry back this of the Gonclufions, to fee what is written therein a-
gainft the Annual motion, which arc to be the argumeats ot our
difcourfc to morrow.

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

G A L I L ^ U S

Galileos Lyncajus^

H IS

SYSTEME

OF THE

WORLD.

The Third Dialogue.

INtEKLOCVroKS.
^ALViATus, Sagredus, and Simplicius.

S A G R.

He great defire wherewith I have expefted
your coming, that i might hear the novel
conceits touching the annual convcrfi-
on of this our Globe, hath made me
think the houres of the laft night, and
thofe of this morning very tedious, al-
though I fpent them not idly, but lying
awake I imployed a good part thereof m

^ -=:==~^ ruminating upon our yefterdayes difcour-

th;''''8^'"gthereafons alledged by both parties, in favour of
contrary Hypothefes, that of ArijiotU and Ftolomy , and
Wh' L ^'•^Prchm, and Copermcm. And really methinks, that
cjT r °^ 'h^fe parties have been deceived, they are worthy of
j^'^">e,fofpeciousand valid in appearance are the reafons that
»y have perfwaded them either way ; though neverthelclTe we

» • do

z^o G. G A L I L ^ u s , /:7ii" S^leme.

for the moft part clofc with thofe produced by the grave Au-
^hoiirs firft above mentioricd. But albeit that the Fenpatetick Hj-
pothefes-, by reafon of its antiquity, hath had many followers and
fautors, and the other very few firft, for its obfcurity, and next,
for its novelty, yet methinks I difcover amongft thofe many,
and particularly amongft the modcrnes Tome, who for thefup'
port cf the opinion by them efteemed true , have introduced
other reafons fufficiently childifli, I could fay ridiculous.

S A L v. 1 have met with the like, and fo much worfc th^^
M^^li'T/tl yours, that I bluft to rehearfe them, not fo much to fpare the fame
winds the cenciH- of thcir Authours, the names of whom might be perpetually con-
thL^trtLi- asbecaufe I am adiamed fo much to ftain the honour of

dapt their rei^etis

niankinde. In obferving of thefc men, 1 have found that fomc
tothnt. there are who prepofteroufly reafoning, firft ftablifli the conclu-

fion in their fancy, and (either becaufe it is their own, or elfe be-
longs to a perfon whom they much confide in) fo firmly imprint
it in their opinions, that it is altogether impoffible ever wholly
efface it : and thofe reafons which they themfelves ftumble upoi^?
or which they hear others to alledge in confirmation of the con-
ceit entertained, though never fo fimple and inf]pid,inftantly fi^^
credit and applaufe with them ; but on the contrary, thofe wH^''
are brought againft their opinion, though ingenuous and cotic\^'
ding, they receive not only with naufeaiing/but with difdain an^
bitter indignation, yea, you (hall have one of thefe fo imaged,
that he will not be backward to try all wayes to fupprefs and filenc^
their adverfaries : and of this I my fclf have had fome experience'
Sagr. Indeed thefe men deduce not the conclufion from tb^
premifes, nor confirme them with Reafons, but accomodate, or
fay better, difcommodate anddiftort the premifes and argumeU^^
to make them fpeak in favour of their prc-afTumed and pertina^^*'
ous conclufions. It is not good therefore to contraft familiari^^/
with thefe men and the rather, for that their converfation is^^^
only unpleafant, but alfo dangerous. Yet let us continue our coP'
ference with 6'z»/p//a;^ however, whom I have known this l^^^g
while for a man of great ingenuity, and altogether void of niali^^^'
bcfides he is well verft in the Peripatctick Doftrine fo that I ^^"1
affure my fclf, that what fhall not fall within the reach of hisre^'
fon for the fUpportof the ^ri/i^^/e/i^;; Hypothefis, will not c^H
be found out by others. But fee yonder he comes, quite out
winde, whofe company we have fo long defircd : we were
fpeaking againft the fmall haft you made to come to us.

Simp. You muft not blame me, but Neptune , for this tnj
«ay ; which in the cbbeof this mornings tide hath in a man"^
drain'd away the waters, for the Gondola that brought me, bc'i"^
entered not far from hence into a certain Channel, wanting i'^^'

Dialogue. II.

Inhere I was ftraiided , and forced to ftay there more than a full
hour, in expcfting the return pf the tide : and there waiting in
^nis manner, without being able to get out of the boat, which on a
Juddcn ran aground, I obferved a certain accident, which to me
jeemcd very ftrange j and it was this, that in the waters ebbing
: retreat very faft by feveral Imall rivolets, the ouze being

jn many places diicovered, and whilft 1 flood looking upon this cf- ''''**f''^hr^fi'

^^^Ifawthis motion in an inftant to ceale, and without a mi-
™tcs interval the fame water to begin to return back again, and
^'le tide trom ebbing to become young flood, without ftanding

ill a moment : an effefi that as long as I have dwelt in Venice^
* "ever took notice of before.

The mithn of
the TfcArer in ehhing
ouze being atfd flowing not tnm

^ A G R. It is very much, that you fliould be left thus on ground,
^ii^ongftfmall Channels , in which rivolets, as having very little
^echvity, the rifing or falling of the main fea, the thicknefs onely

a paper is fufficient to make the water to ebbe and flow for good
i^"g fpaces of time : like as in fome creeks of the Sea, its flowing
our or fix * yards onely, maketh the water to overflow the ad;a-
^^nt Marflies for fome hundreds and thoufands of * acres.

Simp. This I know very well, but I fliould have thought, that
between the ultimate cerme of ebbing, and the firft beginnng to
flow, there fliould have interpofed fome confiderable interval of
reft.

S A G R. This will appear unto you, if you caft your eye upon
Jhebank or piles, where thefe mutations are made perpendicular-
ly> but not that there is any real time of cefTation.
^ Simp. I did think, that becaufe thefe two motions were con-
^'^^y, there ought to be in the midft between them fome kind of
c conformable to the Doftrine o{ ArifiotU, which demonftrates
^nat in piiftSio regrefiis mediat quies.
1^ A G R. I very v^ell remember this place : but I bear in minde
*o, that when 1 read Philofophy, I was not thorowly fatisfied
^'^h ArijiotUs demonftration j but that 1 had many experiments
the contrary, which I could ftill rehearfe unto you, but I am
^ ^Jlling to fally out into any other digreflions, we being met
thef the propofed mattes, if it be poflible, without

^^^ccurfions wherewith we have interrupted our difput(
'^^l^dayes that are paft.
^j^^iMp. And yet we may with convenience, if not interrupt
dav^K^ '^^^ prolong them very much, for returning yefter-
I fi H ^ ^^"^ ^^^^ Traftate of Conclufions,wherc

Ea th ^^'^^^"fttations againft this annual motion afcribed to the
the ^^^^ ^^"'^ ' becaufe 1 would not truft my memory with
P^nftual relation of them, I have brought back the Book a-

5utes m

ton

gwith

me.

li 2

S A G R.

Pertiche venc-

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

^^2, G. G A L I L u s , /:7;a" Sjfleme.

Sagr. You have done very well , but if we woiild rc-affuine
our Difputations according to yefterdayes appointment, it is rc-
quilite thatwefirft hear what account 6 ^^/'i^/^/z/i' hath to give us
of the Book, De ftcllis nozfk^ and then without interiupiion we
may proceed to the Annual motion. Now what fay you, Sahi^'
tus touching thofe ftars > Are they really pull'ddown from Hea^
ven to thefe lower regions, by vertue of that Authours calculati-
ons, whom Simplici^ mentioneth ?

S A L V. I fet my felf laft night to perufe his proceedings) and I
have this morning had another view of him, to fee whether thai
which he fecmed over night to affirm, were really his fenfe, or niy
dreams and phantaftical iioaurnal imaginations ^ and in the clofe
found to my great grief that thofe things were really written and
printed, which for the reputation-fake of this Philofopher I was
unwilling to believe. It is in my judgment impoffible, but that be
fhould perceive the vanity of his undertaking, afwell bccaule it is
too apert, as becaufe I remember, that I have heard him menti<>'
ned withapplaufe by the Academick^our Friend: it feemetb to
me alfo to be a thing very unlikely, that in complacency to others?
he fhould be induced to fet fo low a value upon his reputation,
to give confent to the publication of a work, for which he coul^
cxpeft no other than the cenfure of the Learned.

Sagr. Yea, but you know, that thofe will be much fewef
than one for an hundred, compared to thofe that (hall celebrate^
and extoll him above the greateft wits that arc, or ever liave bee^
in the world : He is one that hath mentioned the Peripat<'
tick inaltcrabihty of Heaven againft a troop of Aftronomersy ant
that to their greater difgruce hath foiled them at their own wea-
pons : and what do you think four or five in a Countrey that Ji*^*
cern his triflings, can do againft the innumerable multinide, tb^f^
not being able to difcover or comprehend them, lujffcr thcmfelv^^
tgbe taken with words, and fo much more applaud him, by bo^
much the lefle they underftand him ? You may adde alfo, tba^
thofe few who underftand, fcorn to give an anfwer to papers
trivial and unconcludent j and that upon very good reafons, l^^"
caufe to the intelligent there is no need thereof, and to thofe rb^^
do not underftand, it is but labour loft,

S A L V. The moft deferved punifhment of their demerits wt^i^f^
certainly be filence, if there were not other reafons, for wbi^^'^
is haply no IcfTe than neccflary to refent their timerity :
which is, chat we Italian f thereby incur the cenfure of IlUter^^^!'
andattraa the laughter of Forreigncrsj and efpccially to ^^^^
who are feparatcd from our Religion j and 1 could flievv yoU
^yf^ot^ of nofmall cmintncy, who fcofF at our Acadefnich
and the nxany Mathematicians that arc in Italic, for fuftering

ate

Dialogue II.

follies of fucha * Fabler againft Jfirommers to cpmc into the
light, and to be openly maintained without contradiftion '5 but
this alio might be difpenfed with, in rcipcft of the other greater
occafions of laughter, wherewith we may confront them depend-
ing on the diflinuilation of the intelligent, touching the follies of
thrfe opponents of the Doftrines that they well enough under-
ftand.

S A G R. I defuc not a greater proof of thofe mens petulancy,
^nd the infelicity of a Copcrnicau, fubjeft to be oppofed by fuch
as underftand not fo much as the^ very firft polStions, upon which
he undertakes the quarrel.

^ ^ 1. V. You will be no lefTe aftoniflied at their method in con-
futing the A^irofjomers, who affirm the new Stars to be fuperiour

the Orbs of the Planets ; and perad venture in the t Firmament
itfdf.

S A G R. But how could you m fo fliort a time examine all this
Sook, which is fo great a Volume, and muft needs contain very
inany demonftrations ?

S A L V. 1 have confined my felf to thefe his firft confutatioqs, in
which with twelve demonftrations founded upon the* obfcrvations
of twelve Aftronomers, (fwho all held, that the Star, Anno 1572.
which appeared in Gapopeia^wsiS in the Firmament^ , he proveth it
On the contrary, to be beneath the Moon, conferring, two by two,
the meridian altitudes, proceeding in the method that you fliall
Underftand by and by. Andbecaufe, I think, that in the exami-
nation of this his fiift progreflion, 1 have difcovered in this Au-
thour a great unlikelihood of his ability to conclude any thing a-
gainft the AJironomers, in favour of the Peripatetick^FbilofopberSy
and that their opinion is more and more concludently confirmed,
I could not apply my felf with the like patience in examining hi$
^tW methods; but have given a very flight glance upon them,
^nd am certain, that the defed that is in thefe firft impugnations,
hkcwife in the reft. And as you fliall fee, by experience, very
words will fufficc to confute this whole Book, though compi^
with fo great a number of laborious calculations, ^^^^
Therefore obferve my proceedings. This Authour under-
^^^^^K as I fay, to wound his adverfaries with their own weapons,
^ great number of obfervations made by themfclves, to wit, by
^^^Ivc or thirteen Authours in number, and upon part ot them he
?^^kcs his fupputations, and concludeth thofe ftars to have been
^.^^ow the Moon. Now bccaufe the proceeding by interrogato-
^erv much plcafeth me, in regard the Authour himfelf is not
l^'^^ Ic^t SimpUcim anfwcr me to the queftions that I fliall ask
f as he thinks he himfelf would, if he were prefcnt. And prc-
^^Ppofing that we fpeak of the forefaid Star, of Anno 1 57a. ap-
pearing

'53

Lorenzini.

f Hetakcthchr
Firmamcni for the
Scarry Sphere, ind
as we vulgarly re-
ceive the word.

The method ok'
ferved kj Clar, tn
confuting the
flronomers^ andhj

fi»g him.

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

2.54 G A L I L ^ u s, his Syjicmc.

peaiing m CaJfiopeia^tdl me, Simpliciu^y whether you believe tha
it might be in the fame time placed in divers places, that is, a-
mongft the Elements, aud alio amongfi the planetary Orbs, and
alfo above thefe amongft the fixed Stars, and yet again infinitely
more high.

Simp. There is no doubt, but that it ought to be confeffed
that it is but in one only place , and at one lole and determinaC
diftance from the Earth.

S A L V. Therefore if the obfervations made by the Aftrono*
mers were exait , and the calculations made by this Author were
not erroneous , it were eafie from all thole and all thele to re-
collet the famediftances alwayes to an hair, is not this true ?

Simp. My reafon hitherto tells me that fo it muft needs be 5
nor do I believe that the Author would contradift it-

Salv. But when of many and many computations that have
been made , there (hould not be fo much as two onely that prove
true, what would you think of them >

Simp. I would think that they were all falfe , either through
the fault of thecomputift, or through the defeft of the obfef
vators , and at the moft that could be faid , I would fay, that but
onely one of them and no more was true , but as yet I know n^^
which to choofe. '

Salv. Would you then from falfe fundamentals deduce afl^
eftablilTi a doubtful' conclufion for ttue ? Certainly no. Now the
calculations of this Author are fuch , that no one of them agrees
with another you may fee then what credit h to be given to
them. °

S I M F. Indeed, if it be fo , this is a notable failing.

Sagr. But by the way I have a mind to \x^\^SimpliciH5, an<l
the Author by telling Salviatus , that his arguments would ho\^
good if the Author had undertook to go about to find out exa'fi'
ly the diftance of the Star from the Earth , which I do not think
to be his intention ; but onely to demonftrate that from thofe
obfervations he coHefted that the Star was fublunary. So
that if from thofe obfervations , and from all the computation^
^ made thereon, the height of the Star be alwayes collefted to be
lefTe than that of the Moon , it fcrves the Authors turn to con*
vince all thofe Aftronomers of moft impardonable ignoran^^^?
that through the defeft either of Geometry or Arithmetick , ^^^^
not known how to draw true conclufions from their own obfe^^^V
tions themfelves.

Salv. It will be convenient therefore that I turn my felf
you, Sagredus^ who fo cunningly aphold thcDoftrineof tbi5
Author. And to fee whether I can make Simplicijis , though not
very expert in calculations , and demonftrations to apprehend

in-

The ^re.ite(i avd
Uafi ehvAtions of
the new fiar d jftr
hot from e:fch o-
ther more than the

O G U

jwJCoiKlafivcncffe at leaft of the demonftrations of this Author^
fiifl piopofcd to confideration , and how 'oo- h he , and all the
Aftrononierb with whom he contendcth, do agree that the new
Star had not any motion of its o^vn , and oncly went round with
the diurnal motion of the pimiimmohik -, but diffent about the
placing of it 5 the one party puttiijg ii in the Cckftial Region,
that is above the Moon? and hapiy above the fixed Stars, and
the other judging it to be neet to the Earth, that is, under the
concave of the Lunar Orb. And bccaufe the lituation of the new
ftar, of which we fpeak, was towards the North, and at no very
great difiance from tjie Pole , fo that to u? Septentrio?ials , it did
never let , it was an eafie matter with Aftronomical inftruments
Mohave taken its feveral meridian altitudes, as well its imalleft
^nder the Pole , as its greateft above the fame h from the compa-
ring of which altitudes , made in feveral places of the Earth,
fifuate at different diftances from the North , that is , different
from one another in relation to polar altitudes , the ftars diftance
"^^ght be inferred : For if it was in the Firmament amonglt the
other fixed ftars , its meridiaxi altitudes taken in divers elevations
of the pole , ought neceffarily to differ from each other with the
fame variations that are found amongft thofe elevation s them- ^^^^^^^.^^^^^
felvcs h thatii>, for example , if the elevation of the ftar above
the horizon was 30 degrees , taken in the place where the polar theFfrw^ment.
altitude was gr, 45 degrees , the elevation of the fame ftar
ought to have been encreafed 4 or 5 degrees in thofe more Nor-
thern! y places where the pole was higher by thefaid 4 or 5 de-
grees. But if the ftars diftance from the Earth was but very little,
in comparifon of that of the Firmament , its meridian altitudes
ought approaching to the North tp encreafe cpnfidcrably more
thai^ the. polar altitudes ; and by that greater encreafe , that is,
^ the excelTe of the encreafe of the ftars elevation , above the
^ncrcafeof the pokr elevation (which is called the difference of
Parallaxes) is readily calculated with a deer and fure method,
^he ftars diftance from the centre of the Earth. Now this Author
f^keththeobfervations made by thirteen Aftronomers in iundry
^kv.itions of the pole , and conferring a part of them at his plea-
J^^e, he computeth by twelve collations the new ftars beight to
^^vebeen alwayes beneath the Moon h but this he adventures to
J^in hopes tp find fo groffe ignorance in all thole, into whole
l^^nds his book mieht come , that to fpeak the truth, it hath turn d
^ ftomack i and 1 wait to fee how thofe other Aftronomers and
1 Particularly Kepler , againft whom this Author principally in-
I ''^igheth , can contein themfelves in filence for he doth not ufe
■ hold his tongue on fuch occafions unkfle he did poflibly

t^f^ink the entcrprize too much below him. Now to give you to

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

2-5^ ^ G. G A L I L ^ u s , Sjfleme.

undciftandthe fame , I have upon this paper tranfcribed the co
clufions that he inferreth from his twelve indagations ; the firft
which is upon the two obfcrvations :

Of Maurolkm and Hain'z.elius , from which
the Star is collefted to have been diftanc from the -
centre lefle than 3 femidiameters of the Earth, '
the difference of Parallaxes being 4 gr. ^2 m.
30 fee, . ^

a. And is calculated on the obfervations of Hain-
r^elins, with Parall. of %, m, 30 fecund its di-
fiance trom the centre is computed to be more
# than ^_ ^

3. And upon the obfervations of Tycho and Hain^
-z.elius , with Parall. of i o and the diftance of

the centre is collefted to be little lefTe than 19 fcmil

4. And upon the obfervations of Tycho and the
Landgra<ve, with Parall. of 14 the diftance
from the centre is made to be about i o femid

5. And upon the obfervations of Hain%elim and
Gemma, with Parall. of 42 m. ^ofec. whereby

the diftance is gathered to be about . ^ femid'

6. And upon the obfervations of the Landara<z^c
and Camcrar^us y^ith Parall. of 8 m. the di-
fiance is concluded to be about - • fem/fi

4 J ■ "

3 femid*

t5 Jemid*

And upon the obfervations of Tycho and Haoe
— with Parall. of 6 m. and the diftance is

made

And upon the obfervations of Hagecim and Vr-
finm with Parall. of 43 m. and the ftars diftance

from the fuperficies of the Earth is rendred

And upon the obfervations of Landgra^vius and
Bufchim , \yith Parall. of 15 m. and the di-
ftance from the fuperficies of the Earth is by
fupputation ■ —

31 femid'

\ femid'

And upon the obfervations of Maitrolice and
Mnnocius, withParalJ. of ^m. fee. and the

computed diftance from the Earths furface is . femtd.

»i; And upon the obfervations of MHnoeim znd '
^^mma with Parall. of 55 and the diftance
irom the centre is rendred ^ ^ j^^mid^

And

-^3

13. And

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2°K.B. 9,163

Dialogue III.

12. And upon the obfervations of Uunofim and
Vffinm with Parall. of i gr. 36 m, and the di-
ftance from the centre cometh forth leffe than — 7 femid.

Thefe are twelve indagations made by the Author at his elefti-
on, amoagftmany which, as he faith, might be made by combi-
ning the obicrvations of thefe thirteen obfervators. The which
twelve we may believe to be the moft favourable to prove his
intention.

S A 0 R. I would know whether amongft the fo many other in-
^lagations pretermitted by the Author, there were not fome that
made agaiaft him , that is, from which calculating one might find
the new ftar to have been above the Moon , as at the very firft
fight £ think we may reafonably queftion in regard I fee thefe
already produced tobefo different from one another , that fome
of them give me the diftance of the faid ftar from the Earth, 4, 6,
ICO, athoufand, and an hundred thoufand* times bigger one
than another fo that I may well fufpea: that amongft thofe that
he did not calculate , there was fome one in fauour of the adverfe
party And I gueffe this to be the more probable , for that I can-
not conceive that thofe Aftronomers the obfervators could want
the knowledg and praftice of rhefe computations , which 1 think
do not depend upon theabftruceft things in the World. And in-
deed it will feem to me a thing more than miraculous , if whilft in
thefe twelve inveftigations onely , there are fome that make the
ftar to be diftant from the Earth but a few miles , and others that
make it to be but a very fmall matter below the Moon , there are
none to be found that in favour of the contrary part do make it
fo much as twenty yards above the Lunar Orb. And that which
ftallbe yet apain more extravagant , that all thofe Aftronomers
ftiould have been fo blind as not to have difcovered that their fo

^Pp?irent miftakc. , -.k

S.Lv. Begin now to prepare your ears to hear with nfin te
admiration to what exccffes of conRdence of ones own authority
and others folly , the dcfue of contradiaing and flvcwing ones
felf wiler than others , trartfports a man. Amongft the mdaga-
tions omitted by the Author , there are fuch to be found as make
the new ftar not onely above the Moon , but above the hxed
ftars alfo. And thefe are not a few , but the greater part, as you
Mice in this other paper, ^^ere 1 have fct them down-

S*oK. But what 4h the Author to thefe? It may be he did
not think of them ? " . . , ... . ,

S A L V. He hath thought of them but too much . but fa,th,that
the obfervations upon which the calculations make the ftar to be
infinitely remote, are erroneous , and that they cannot be com-
'^■'ned to one another. ^ k Simp-

G* G A L I L ^ u Im Syjlcme.

Simp. But this feemeth to me a very lame evafion ^ for the ad-
verfe party may with as much reafon reply , that thofe are errone-
ous wherewith he collefteth the ftar to have been in the Elemen-
tary Region*

S A L V. Oh Simplicipfs , if I could but make you comprehend
the craft , though no great crafcinefTe of this Author , 1 ihould
make you to wonder , and alfo to be angry to fee how chat he
palliating his fagacity with the vail of the fimplicity of your felfi
and the reft of meer Philofophers , would in iinuate himfelf into
your good opinion, by tickling your ears , and fwelling your am-
bition 5 pretending to have convinced and filcnced thcfe petty
Aftronomers, who went about to affault the impregnable inalte-
rability of the Peripatetick^ Heaven , and which is more, to have
foild and conquered them with their own arms. I will try with all
my ability to do the fame, and in the mean time let SagredttS
take it in good part , if Simplicim and I try his patience, perhaps
a little too much , whilft that with a fuperfluous circumlocution
(fuperfluous I fay to hii> moft nimble apprehenfion) 1 go about to
make out a thing , which it is not convenient fliould be hid and
unknown unto him,

Sagr. I (hall not onely without wearineffe , but alfo wit^
much delight hearken to your difcourfes i and fo ought all Perif^{
tetich^ Philofophers , to the end they may know how much th^I
are oblieged to this their Proteftor.

S A L V. Tell me, whether you do well comprehend^

how, the new ftar being placed in the meridian circle yonder to-
wards the North , the fame to one that from the South ftould
go towards the North , would feem to rife higher and higher r
hove the Horizon , as much as the Pole , although it (hould haV^
been fcituate amongft the fixed ftars j but, that in cafe it
confiderably lower , that is nearer to the Earth , it would appei'^
to afcend more than the faid pole , and ftill more by how
its vicinity was greater ?

S I M p. I think that I do very well conceive the fame i in to-
ken whereof I will try if I can make a mathematical Scheme
it, and in this great circle [in Fig: i. of thk Dialogue.'] I w'il^
markc the pole P j and in thcfe two lower circles I will note VS^
ftars beheld from one place on the Earth , which let be A j
let the two ftars be thefe B and C, beheld in the fame line A ^ ^'
which line I prolong till it meet with a fixed ftar in D. And then
walking along the Earth, till I come to the jterm E , the tw<>
ftars will appear to me feparatcd from the fixed ftar D , and ad-
vanced neerer to the pole P , and the lower ftar B more , which
will appear tome in G , and the ftar C leffe , which will ap
pear to me inF, but the fixed ftar D will have kept the fai^e
diftance from the Pole . Sal V.

■I

I A L O (5 U E

Hi.

159

S A L V. I fee that you an

derftand the bufineffc very well. I be

:henJ , that, in regard the ftar B

lievethatyoudo likewile compreL-^ ,
islowcF thanC, the angle which is made by the rayes

of the

"ght , " which departing (torn the two places A ana IL , meet m C,
to wit, this angle A C E , is more narrow , or if we will fay more
acute than the angle conftitutcd in B , by the rayes A B and
E B

Si mp. This 1 likewile underftand very Well. \ ^
S A L V. And alio , the Earth beine very httle and almoft .nfen-
fible, in relVeft of the fcirmamcnt (or Starry Spbere;) and con-
sequently the fpacc A E , paced on the Earth , being very Imall m
comparifon of the immenfe length of the lines E G and L b , pal-
ling frou. the Earth unto the Firmament , you thereby collefi that
the ftar C mieht rife and afcend fo much and fo much above the
•Earth, that the angle therein made by the rayes which depart
from the laid ftationary points A and E , might become molt a-
cute , and as it were abfolutcly null and inlenfible.
S I M 1.. And this alfo is moft manifcft to fenlc.
S A L V Now you know SimpUcius that Aftronomers and Ma-
theimtkians havc found infallible rules by way of Geometry and
ArSe Tk, to be able by help of the quant ty of thefe angks
B arid C , and of their differences , with the add.t.oixal knowled^
of thediftance of the two places A and E , to find to a foot the
tcmoteneflc of fublimc bodies i provided alwayes that the atore-
faiddiftance, and angles be exaaiy taken.

S i M p. So that if the Rules dependent on Geometry and Jjtror
nomy be true, all the fallacies and errours that might be met witQ
in attempting to inveftigate thofe altitudes of new Stars or Co-
mets, or other things muft of neccflity depend on the d'ftance A E,
and on the angles B and C, not well mealured. And rhu. all thofe
differences wl^.ch are found in ^hefe twelve workings depend no
on the defeas of the rules of ,he Calculat.ons ^j^e e^our
committed finding out thofe angles,and thofe d>ftances,by means

no aoubt tobe .a.e.^ N^^^
itisneceffarythatyouoblerveinter^,^^^^^^^^^^^^
from B to C, whereupon the angle alwayes grows m £^
^ay E B G goeth farther and farther off from ray A m
part beneath the angle, as you may '^/^^'^ '"^'c than
-Me inferiour part E C rs mo. remoce from he pa t A C^than

^ach other, ey being finally to go and conjoyn tn the Star : and
onely this may be fail, that they would feparate, and reduce them
fclves to parallels, if fobethe recea.on^lhould be irtfin.tc, which

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

' Impcrccpiibic,

2-^0 G. C A L I L ff. u s, his Syflcme.

cafe is not to be fisppofed. But becaufe (obfcrvc well) the diftance
of the Firmament, in relation to the flnallneffe of the Earth, as
hath been laid, is to be accounted, as if it were infinite ; tlrxcfore
the angle conteined betwixt the two raycs, that being drawn from
the points A and E, go to determine in a fixed Star, is dtcancd
nothtng, and thofe rayes held to be two parallel lines ; and there-
tore It IS concluded, that then only may the New Star be alHrBied
to have been ,n the Firmament, when from the collating of the
Oblervations made in,divers places, the faid angle is, by calcuJa-
non, gathered to be infenfible -and the lines, as it were, parallels.
But ,i the angle be of a eonfiderable quantity, the New Star muft
of neceffity be lovver than thole fixed, and alio than the Moon, m

cafe the angle ABtfliouId be greater than that which would be
made in the Moons centre.

S I M r. Then the remoteneffe 6f the Mr^^t. • r l *j

1-1 in 1 1 1 ;k . , vji tne iVioon IS not lo area that'
a hke angle fliouid be ' inienfible in her ? ^icac,cu

in th^eVun^lfo'"'^ ^-^^^^ - ondy .„ the Moon, bac

, S .MP. But if this be fo, its poffible that the faid angle mft
beobferved ,n the New Star, without neceffitating it to be infefi^
our to the Sun, afwell as to tlic Moon.

V '"nJ"n?'' ""7 '^7 "^"^ 1*^' y'^' ''"'^ Prefent cafe |

as you ftall fee .n due place ; that is, when I ftall have made plain

5;rSScrr4t^^^^^^^^ -y perffa.

your hands feel how that 'this Ltul^ la Thr;^^^^^
write m complacency oi the Penpatetich bv n,n- A A\(,

fembHnglundry things, than toeftablilhl'etr'uK 'r^'. t

them with naked fincerity : thereforelet us proceed IZt ii

the thjngs hitherto fpoken, I fuppofe chat y'ou compXd

wen how that the diftance of the new Star can never be

madefonnmenfe, that the angle fo often named ftall wholly dif-

SF'Sf^U r "^'u Obfervators at the Jlace.

A and E, fliall become altogether parallels : and you may confe-
quently comprehend to the full, that if the calLlat ons ftoulJ
coUea fi^mtheobfervations, that that angle was totally null, or
that the lines were trulv parallels, we ftould be cert in that ti'
obfervations were atfeaft in fome fmall particular ""roncoU^--
But, ,t the calculations fliouId give us the faid lines to be icP^'"^'
htr'al^ toequ,diftance,thatis, fo as to be parallel but to
below ,u ^^°"^'^,'"T''' ^^'^^'^ be dilated more above than
were m '^^^ refolutely concluded, that the obfervation.

ous • .^rrj.'f'^l^fl^accurateneire, and inaword, to be erronc-
you muft bfe":;: 'Zf^ ;.'"Pf bility. In the next place,
^ me, and fuppole it for true, that two right Ymes

which

Dialogue. III.

Hich depart fiom two points marked upon another right linc^ are
^hen wider above than below, when the angles included between
4em upon that right line are greater than two right angles j and
if thefe angles ihould be equal to two right angles, the lines would
be parallels , but if they were lefs than two right angles, the lines
Would be concurrent, and being continued out would undoubted-
ly interfcft the triangle.

Simp. Without taking it upon truft from you, I know the
fame and am notfo very naked of Geometry ^ as not taknow^a
Propofuion, which I have had occafion of reading very often in
^rzftotle, that is, that the three angles of all triangles are equall to
two light angles ; fo that if I take in my Figure the triangle ABE,
'^^ being luppoied that the line E ^ is right ; I very well conceive,
^bat its three angles A, E, B, are equal to two right angles h and
^hat confcquently the two angles E and A are leffe than two right
^i^gles, fo much as is the angle B. Whereupon widening the lines
A B and E B fftill keeping them from moving out of the points A
andEj untill that the angle conteined by them towards the parts
^3 dilappcar , the two angles beneath (hall be equal to two right
ingles, and thofe lines fliall be reduced to parallels : and if one
fliould proceed enlarge them yet more , the angles at the points
E and A would become greater than two right angles.

S A L V. You are an Archimedes , and have freed me from the
expenceof more words in declaring to you , that whenfoever the
calculations make the two angles A and E to be greater than two
nght angles , the oblcrvations without more adoc will prove erro-
neous. "tIVis is that which I had a defire that you fhould perfcft-
ly underftand, and which I doubted that I was not able fo to make
out, as that ameer FeripateUcl{^?hi\otophcr might attain to the
certain knowledg thereof. Now let us go on to what remains.
And re-afTurain^ that which even now you granted me, namely,
*at the new fta^r could not po(ribly be in many places , but m anc
, when ever the fupputations made upon the obfervatio^ ot
^•^efe Aftronomcrs do not aQign it the fame place , its neceflary
^Jat it be an errour in the obfervations, that is, either in takmg the
altitudes of the pole , or in taking the elevations of the Itar , or m
one orother working. Now for that in the many workings
nude with the combinations two by two , there are very tew ot
'l^^obfervations that do agree to place the ftar in the fame fitua-
'*^n therefore thefe few onely may happily be the non-errone-
' hue the others are all abfolutely falfe.
Sagr. It will be neceffary then to give more credit to thefe
alone , than to all the reft together , and becaufe you fay,
^bat thcfc which accord are very few , and 1 amongft thefe i ^»
^o find two that fo accord , which both make the diftancc of the

ftar

i6i

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

^6^

G. G

A L I L iEU S

his SjfJi

'erne.

ftar from the ccnrre of the Earth 4 femidiamcters , which arc chefe,
the fifth and fixth , therefore it is more probable that the new Aar
was elementary , than celeftial. i

S A L V. You miftake the point ; for if you note well it was not
written, that the diftance was exaftly 4 femidiamcters , but about
4 femidiamcters i and yet you fliall fee that thofe two diftances
differed from each other many hundreds of miles. Here they are;
you fee that this fifth, which is 13389 It a/iau miks , exceeds the
fixth, which is 1 3 1 00 miles, by almoft 300 miles.

S A G R. Which then are thofe few that agree in placing the ftar
in the fame fituation > r &

A LV. They arc, to the difgraccof this Author five workings,
which all place ,t m the firmament , as you fliall fee in this note,
where I have let down many other combinations. But I will grant
the Author more than peradventure he would demand of me,vvhich
IS inlum, that in each combination of the obfcrvations there's
lome error i which I believe to be abfolutely neceflkry ; for the
obfcrvations being four in number that ferve for one working,
that is, twodiflferent altitudes of the Pole , and two different eleva-
tions of theftar, made by different obfervers, in different pU-
_Afir,mmicAi h.. CCS, With different inftruiTients , who ever hath any fmall knoW-
S::rr' if '^g f ^'^'^ > ^^^^ t^at amonga all the four, it is impoffible
but there will be fome error j and efpecially fince we fee thatin
taking but one onely altitude of the Pole , with the fame inftru-
ment, ,n the lame pUce by the fame obferver , that hath re-
peatcd the obfervation a thoufand times , there will ftiH be a titii
bation of one , or fometinics of many minutes , as in this fam.
book you may fee ,n Icveral places. Thefe things prefuppofe<Ji
I askyou5/w;)/«/«i- whether you believe that this Authourhel'f
thefe thirteen obfcrvators for wife, underftanding and expert me"
in ufing thofe inftrumcnts , or clfe for inexpert, and bunglers ?

Sr M p. It muft needs be that he eftecmed them very acute
intelligent i for if he had thought them unskilful in the bufinefle,
he might have omitted his fixth book as inconclufive as being
founded upon fuppofitions very erroneous ; and might take usfo'
exceffively fimple , if he fliould think he could with their ine«-
pertneffe perfwade us to believe a falfe pofition of his for truth-

Sal v. Therefore thefe obfcrvators being fuch and thaty^'^
notwithftanding they did erre , and fo confequently needed ^or-
ycaion , that fo one might from their oblervations infer the
oefthintsthatmay be; it is convenient that we apply unto thein
f ^rh i.^"*^ weexa^L emendations and correaions that inayb^'
10 tnatthey do butfuffice to reduce the obfcrvations fromimpol'

Tft Pn-ollr"''^^'"^ ' ^° '^orr-^a a mani-

icltcrrour, and an apparent impoffibility of one of their obfer-

vation*

Dialogue. III.

''»tionsby the addition or fubftraaion of tWo or three minutes,and
with that amendment to reduce it to poffibility, a man ought
lotto effay to adjuftitby the addition or fubftra£iion of fifteen,
twenty, or fifty.

Simp'. 1 thmk the Authour would not deny this : for granting
that they are expert and judicious men, it ought to be thought that
'hey did rather erre little than much.

S A L V. Obferve again ; The places where the new Star is pla-
ced, are fome of them manifeftly impoffible, and others poffible.
Abfolutely impoflible it is, that it ftiould be an infinite fpace lupe-
riour to the fixed Stars, for there is no fuch place in the world \
and if there were, the Star there fcituate would have been imper-
ceptible to us : it is alfo impoflible thir it ftiould go creeping along
the fupcrficies of the Earth i and much leife that it fliould be
within the laid Terreftrial Globe. Places poffible are thefe that
1^ in controverfie, it not int.rferring with our underftanding, that
3 vifible objeft in the likeneffe of a Scar might be afwell above the
'^oon, as below it. Now whilft one goeth about to compute by
the way of Obfcrvations and Calculations made with the utmoft
certainty that humane diligence can attain unto what its place was,
it is found that the .greateft part of thofe Calculations make it
more than infinitely luperiour to the Firmament, others make it
Very necr to the furface of the Earth, and fome alfo under the
r»me j and of the reft, which place it in fituations not impoflible,
none of them agree with each other ; infomuch that it muft be
confefl"ed, that all thole obfcrvations are neceflarily falfe i fo that
'f we would neverthelefs colleft fome fruit from fo many laborious
calculations, we muft have recourfe to the correaions, amending
all the obfcrvations.

S I H p. But the Authour will fay, that of the obfcrvations tliat
»flign to the Star impoflible places, there ought no account to be
niade, as being extreamly erroneous and falfe , and thofe onely
^ht to be aLpted, that conftitute it in places not impoflible .•
'"d amongft thefe a man ought to feck, by help W the moft pr«>.
^»Me, and moft numerous concurrences, notif the particular and
^'''^afituation, that is its true diftance from the ^^"^^1^^
£"th, at leaft, whether it wasamongft the Elements, or elfe a-
"'ongft the Coelcftial bodies. . . .. r

, Salv. The difcourfe which you now make, is the ielt lame
?»t the Author made, in favour of his caufe, but with too unrea-
^°«*l>le a difadvantag; to his adverfaries ; and this is that prmci-
P^^l point that hath mlde me excefllvely to wonder at the too great
\«nfidence that he exprelTed to have, no lefs of his own authority,
2»anoftheblindnefs and inadvertency of the Aftronomcrs ^ in
*^vour of whom I will fpeak, and you (hall anfwcr for the Author^

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

G. Galil^us, his Sjfleme.
And firft, I ask you, whether the Aftronomers, in obferving with
their Inftruments, and reeking 5/ .^r. how great the elevation of a
Star n above the Horizon, may deviate from the truth afwell in
maknig it too great, as too little ; that is, may erroneoufly com-
pute, that It .s iometimc higher than the truth, and fometimes low-
er; or cite whether the errour muft needs be alwayes of one
k,nde, to w,t, that erring they alwayes make it too much, and ne-
ver too little, or alwayes too little, and never too much >

S I M 1.. I doubt not, but that it is as eaOc to commit an errour
the one way, as the other.

^^^"IJ anfwer the fame. Now of
thefe two kinds of errours, which are contraries, and into which tic
obfervators of the newftarmay equally have fallen applied to

han really 1 IS. And becaufe wc have already agreed, that all

that^hewtheftartofavebeent^tlTrS^^^^^^^^^
fliew It excefllvely remote >

1 r.^ ' " "'.uK^^a' I''' r'/' °f A"t'>ors mind,

? t doth rcfufe thofe obfervations, and indagation'
itT. I't "^t^^*^^ ft^^'T^^/emote than the Moon, and alfo
than the Sun, but only thofe that make it remote (as you yourfcl^
have faid) more than an infinite diftance ■ th^ u j a ^ he-
caufe you'alfo do refufe it as impoSe' he alf V f I
being convificdof infinite- falftS ' : ''f/'^^ P^^ffeth over, a
areof impoffibility. Methirkftheref. u obfervat.ofl=
vince the Author, you ought JltoTucrfu^^.r/- ^'^"^'^
or more in number, or of more dygen?oterT\"'"'^''^^^
the ftar in fnrh and fnrU . A n. ^^'ervcrs, which conftitute

tne itar in luch and luch a diftance above the Moon, or above tbf

Sun and to be bnef,inaplacepoinbJefor it to be in like Ts
produceth thefe twelve, which all place the ftar bene h he M^''
inphcesthat have abeing in the world, and where it is poffibJe for

^IJover by y Jur fpeech tha^ fot' ht t^dt^ilcertf^^^
fclf that the exorbitancies that are commited in the eftablii^i"g
the diftance of the Star do cncreafe fucceflively, accordW t« the
proportion of the errors that are made by the Inftrumen in tak-
'ng heobfervations, and that by converfion, fromTgr atnef^
and tS^'T''?' r^b^-^g"-'^the greatneffe of h^e error.

theerroi?rnil%t1r'°^^'^"^'^ it is neceffary, th»t
^'''"vmg was infimte, and therefore not to be amend-

lALOGUE III.

1^5

[Of

cd, and asfuch to be refufed ^ but the bufinefle doth not fucceed
in that manner, my Simplicim, and I excule you for not having
comprehended the matter as it is, in regard of your fmall experi-
ence in fuch affairs , but yet cannot I under that cloak palliate the
error of |:Jbe Author,who dilfembling the knowledge of this which
he did pcrfwade himfelf that we in good earneft did not under-
ftand, hath hoped to make ufe of our ignorance, to gain the bet-
ter credit to his Doftiine, among the multitude of illiterate men.
Therefore fpr an advertifement to thofewho are more credulous
then intelligent,and to recover ygu from error, know that its pof**
fiWe ( and that for the moft part it will come to paffe ) that an
pbfervationv that giveth you the ftar 'z/. gr. at the diftance of Sa-
^Hr/i, by the adition or fubftraftion of but one folc minute from
tfoe elevation taken with the inftrument, fliall make it to become
infinitely diftant h and therefore of poITiblc, impoffible, and by
converfion, thofc calculations which being grounded upon thof^
obfervatiQns, make the ftar infinitely remote, may pofiibly often-
times with the addition or fubduaion pf one folc minute, reduce it
^ a poflible fcituation and this which I fay of a minute, may al-
fo happ<?n.in the correaion of half a minute, a fixth part,and lefs.
Now fix it well in your mind, that in the higheft diftances, that;$
V. g. the height of Saturn, or that of the fixed Stars, very fmall
errors made by the Obfcrvator, with the inftrumcnt, render the
fcituation determinate and poflfiblejinfinite & impoffiblc. This doth
not fo evene in the fublunary 4iAances, and near the earth, where
it ma) happen ;hat tjie Qbfcrvation by which theStar is coUefted to
be remote ^. 4. j^f midiameters terrefcrial, may encreale ordimi-
«i(h, not onely one minute but ten, and an hundred, and many
more, without being rcndred by the calculation either infinitely
remote, or fo much as fuperior to the Moon. You may hence
Comprehend that the ^reatncOb^of the error (tofofpcak) inftru-
mental, are not to be^alued by the event of the calculation, but
by the quantity it felf of degrees and minutes numbred upon the
inftrument , andthefe obfervations are to be called more juft or
lefs erroneous, which with the addition or fubftraaion of fewer
«iinutes,reftore the ftar tp a poflible fituatiooi and amongft the
PoOible places,the true one may.be bdicved to have been that, a-
bout which a greatpr.number of diftances concurre upon calcula-
ting the more exaa obfervations. 1.1 r

Simp. I do not Kery well apprehend this which you lay : nor
I of my felf cojvceive how n can be, that in greater diftances,
g;^ater exorbitancie^^can afifefrpm the errour of one minute only,
tl^^n in the fmaller from ten or an hundred and theretore would
gladly

Underftand the fame.
S A L v. You (hall fee it, if not Theorically, yet at Icaft Praai-

L I caUy^

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

z66 G. G MIL ^usy his Syllcmc.

cally, by this (hort afflimption, that I have made of all the combi-
narions,andof partof the workings pretermitted by tNfe Author,
which 1 have calculated upon this lame paper.

S A G R. You muft then from yefterday, till now, which yet is
not above eighteen hours, have done nothing but compute, with-
out taking either food or flcep.

Salv. Ihaverefrefliedmy felf boththofe waycs •, but truth is,'
make thefe fupputations with great brevity j and, if I may fpeak
the truth, I have much admired, that this Author gocth fofarre a-
bout, and introduccth fo many computations no wife necefsary to
the queliion in difpute. And for a full knowledge of this, and al-
fo to the end it may foon be feen, how that from the obfervations
of the Afironomers, whereof this Author makes ufe, it is more pro-
bably gathered, that the new ftar might have been above the
Moon, and alfo above all the Planets, yea amongft the fixed ftars,
and yet higher ftill than they, 1 have tranfcribed upon this paper
air the obfervations fet down by the faid Authour , which were
made by thirteen Aftronomers, wherein are noted the Polar alti-
tude, and the altitudes of the ftar in the meridian, afwell the
lefTer under the Pole , as the greater and higher , and they arc
thefe.

Altitude of the Pole
Altitude of the Star

Tycho,
^7

And thefe are, according to
the firft paper : but accor-
ding to the fecond, the
greateft is 27

00
57

the greateft.
the leaft.

Haim^elius.

Altitude of the Pole
Altitude of the Star

48 a2

fee.

76 3+

75 33 45

7^ 35
ao

10 op go

ao op

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Images reproduced by courtesy of the Royal Library, Copenhage
2°K.B. 9,163

Dialogue, lit;

Peucerm and Scnkrus.

gr, m.

Altitude of the pole 51 54

Altitude of the Scar 7^ 56

^3 33

LandgramHS.

gr. m.

Altitude of the pole 51 18

Altitude of the Star 79 30

Camerarius.

gr. m.

Altitude of the pole 52 34

Altitude of the Star 80 30

80 37

80 a(5

24 a8

Altitude of the pole
Altitude of the Star

»5

Maurolycfis.

Altitude of the pole
Altitude of the Star

38
6a

30
00

Hnnocius.

Altitude of the pole
Altitude of the ftar

^7
1 1

3°

'Vrjtnus.

gr. m.
Altitude of the pole 49 34
Altitude of the ftar 79 00

aa 00

Keinholdus.

^jtitude of the pole
A"«ude of the ftar

79
33

tn.

18
30
oa

BucbiMt.

Altitude of the pole $1
Altitudeof the ftar 79
aa

Ctmtna.

Altitude of the pole $0
Altitude of the ftar 19

LI a

Mr.

xo
ao
40

25S

G. Galil/euSj his Syjleme.

Now to fee my whole proceeding, we may begin from tbefi
calculations, which arc four, omitted by the Author, perhaps be-
caafcthey make againft him, in regard they place the ftar above
the- mckjn by many femrdiameters of the Earth. Tlie firft^
which h this, computed upon the obfervatkms of the Lahdgrave of
Hajpa, Tind Tycho which are, even by 'the Authors conceQlon?
two of the moft exaft obfervers : and in this firft, I will declare
the order that I hold in the working .which (hall ferve for all the
reft, in that they arc all made by the fame rule, not varying in any
thing, favein the quantity of the. giveuriftiixunes, that is, in the
number of the degrees of the Poles akitide; and of the new Stars
elevation above the Horizon, the diftance of which from the cen-
tre of the Earth, in proportion to the femidiameter of the terre-
ftrial Globe is fought, touchi^ which it nothing imports in this
cale, to know how many miles that femidiameter conteineth;
whereupon the refolviiig that, and the diftance of places where
the obicrvationswere made, as this Author doth, is but time ana
labour loft ; nor do 1 know why he hath made the fame and efp^'
cially why at the l^ift.h.c goech about to reduce the mUcs foundjin?
to (emidiameccrs of the Terreftrial Globe.

S I M p^. Perhaps he doth this to findc with fuch fmall meafurei
an4,wh^ theitifa^fJoAs the diftanc^ of theiStai ttrminated to thfC-
Of fouchiches ;^^ivv*6 tiifft do not^nderiknd your rules of Arit^-
metick, are ftupifiedin hearing your conclufions as for inftanc^j
whilft we rea4 i Therefore the new Star or Comet was diftant
from the Earths centre tKreehundr^ three thoufana

eight bupdred and (even miles^r and moreover, two hundred ana
4ayer^/oL^thoufendnmety fcvenths 373807 and upon theft
precilepunaualities, wherem you take npcice of fiich> fmall mat'
wn, we^do conceive ii to be impoflible, tlmt you, who in our cal'
culations keep an account of an inch, can at the clofe deceive us
much as an hundred miles.

S A L V. This your reafon and excufe would paffe for currant,
i^in a diftance of thoufandsof miks, a yard over or under wef^
(?^,any^rea£:w>n)Wv^nd if 4he fuppoftions that we take f^^^
Uue, >verc io cert4m,^.as that they could affure us of producing
influWuble truth m the conclufion^ but here you fee in the twelve
workmgs of the Author, the diftances of the Star which botn
them one may conclude to have been different from each other,
(and therefore wide of the truth) for many hundreds and thou-
fands of -miles ; now whilft that 1 am more than certain that that
which 1 feck muft needs differ from the truth by hundreds of mil^^'
to whatpurppreisittobe focun^^^^ our calculations for f^ar
I milling the quantity of an inch? But let us proceed, at lafe
to the working, which I refolve in this manner. Tycho, as mayb^

{ecn

I
I

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2°K.B. 9,163

Dialogue Hi.

fccn in that fame note oblerved the ftar in the polar altitude of 55
degrees and 58 mi. pt. And the polar altitude of the Landgrave
was 5 1 degrees and 1 8 wn. f r/. The altitude of the ftar in the Me-
ridian taken by 7ycho was 27 degrees 45 mi, pi- The L<iwrf-
gravc found its altitude 23 degrees 3 mi, pri. The which altitude^
are thcfe noted here, as you fee.

Tycho
Landgr.

Pole
Tole

45
3

This doncfubftraa the Icffe from the greater, and there remains
thefc differences here underneath.

gr. m.

4 40
4 4^
Parall. a

Where the difference <tf the poles altitudes 4 gr. j^ mi. fr.
is leffe than the difference of the altitudes of the Star A,gr. 42 mi.
pr. and therefore wc have the difference of parallaxes , ogr. a mt.
fri: Thefe things being found , - take the A^ithours own figure
rpi„, a.] in which the point B is -the ftation of the Landgra've,
D theftation of Tycfeo , C the place of the ftar , A the centre
of the Earth , A BE the vcrtkallinc of the Landgrave., A D F

Ang. BAD 4
BDF 92

BDC'V^V
BCD o

m.
40
30

, Its chord Si 41 of thofe
pwts, wUereof ihe ljieowd..,
A B is an 100000.

Sines

42657
58

5«

4«^57
814a

85314
170628
42657
341256

142

59
3473

[3294

^ycho , and the angle B C D the difference of Parallaxes. And

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

G. G A L I L u his Syjlcmc.

becaufe the angle BAD, contcined between the vertical lines, is
equal to the difference of the Polar altitudes, it (hall be A^gr. A^om.
which I note here apart ^ and I finde the chord of it by the Tabic
of Arches and Chords, and fct it down neer unto it, which is 814a
parts, of which the femidiameter A B is 100000. Next, I finde
the angle B D C with eafe, for the half of the angle BAD, which
is a gr, ao «/. added to a right angle, giveth the angle B D F 92gr.
20 m, to which adding the angle CDF, which is the diftance from
the vertical point of the greateft altitude of the Star, which here is
^2 ^r. 15 m, it giveth us the quantity of the angle BDC,
I'i^grad.j^t^ min. the which I fet down together with its Sine,
taken out of the Table, which is 4^657, and under this I note
the angle of the Parallax B C D o ^r. 2 with its Sine 58.
And becaufe in the Triangle BCD, the fide DB is to the fide
B C j as the fine of the oppofite angle BCD, to the fine of the
oppofitc angle B D C : therefore, if the line B D were <8. B C
wouldbe4a657. And becaufe the Chord DB is 8142. of thofe
parts whereof the femidiameter B A is 100000. and we feek to
know how many of thofe parts is B C ; therefore we will fay, by
the Golden Rule, if when B D is 58, B G is 42657. in cafe' the
faid D B were 8142. how much would B C be ? 1 multiply tbc
fecondtermby the third, and the produfi is 3473132^4. which
ought to be divided by the firft> namely, by 58. and the quotient
(hall be the number of the parts of the line B C, whereof the fc'
midiameter A B is 100000. And to know how many femidiafliC'
ters B A, the faid line B C doth contein, it will be neceflary aneW
to divide the laid quotient fo found by 1 00000. and we ftallhavc
the number of femidiameters conteined in B G. Now the num-
ber 347313294. divided by 58. giveth 5988160;. as here you
may fee.

5988 1

5^1 347313294
571794^
643

And this divided by 1 00000. the produft is t^pA'M;
i|ooooo I 59 1 8S160.

But we may much abbreviate the operation, dividing the
quotient found, that is, 347313294. by theproduft of the multi'
phcation of the two numbers 58. and 1 00000. that is,

DlALOGtlt. III.

58;oooool 3473 1 13294.
5

And this way alfo there will come forth 'i9',^iii±

And fo many femidiameters are contained in the line B C, to
which one being added for the line A B, we (hall have little leffc
than 61. femidiameters for the two lines ABCi and therefore
^l^e right d'lftance from the centre A, to the Star C, (hall be more
than 60. femidiameters, and therefore it is fuperiour to the Moon,
according to Ftolomy^ more than 27. femidiameters, and according
Copernicus^ more than 8. fuppofing that the diftance of the
Moon from the centre of the Earth by CofernicHS his account is
what the Author maketh it, 52 femidiameters. With this lame
working, I find by the obfervations of Cameravius^ and of Marto-
^«*5 that the Star was fituatc in that fame diftance, to wit, fome-
what more than 60. femidiameters. Thefc are the obfervations,
and thcfe following next after them the calculations.

DilFcrcnces of the
lar Altitudes

anc

Altitude of cCamerar.
the Pole iMunof.

gr. m.\ , - gr. m.
52 24' Altitude of c 24 28

39 30'

12 54

the Star ^ 3^

Differences ci2 58
of thealt.of:J^2^2 54

Difference of Parallaxes ^oq 04. ang.BCD.

gr. m.

f B A D 12 54 and its chord or fubtenfe 224^6.
Angles^BDC 161 cjnes | ^0^30

^BCD 00 04) ^'""^ I

Ihc Golden Rule

22466
ira 30930 ' 22400

Vr r; 673980

^ . ao2i94

, 67398

Diftance B C 59. and

116 I 6948 \ -73380 almoft 60. femidiameters.
10

The

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

G. Galil/eus, his Sjfleme.

The next working, is made upon two obfcrvations of TycJ&Ojand
ot Munofius, from which the Star is calculated to be diftant from
the Centre of the Earth 478 Semidiameters and more.

gr. m.

Altitudes Klycht. 55 58
of thcPole. ^M««o/. 39 30

gr. m.

Altitude C 84 00
of the Star. $67 50

DifFerencesofthc^ l Difter7of the? 1^30

Polar Altitudes. \ \ au. of the^ x6

gr. m. —

A J Spnr'*^ «S chord 28640
Angles <B P C. 104 147 t

: : ^BCP. o J ? Sines 5 ^^^30

4«

a8<54o ^

3877aop
58,58
77544

478

' 7510©

45°^

trc TI;^!; r'^'^^Q ^f^'T^ S^^*^ ^^"^^^^ the Cen-

tre, more than 358 Scmidametcrs.

gr. m.

Altitudes KPeucer^s ^ i 54
of the Pole. {Mnnopus 39 30

13 14

Altitude ijp 5 5
of thcv^ ^47 30

I a 24

B 4D. I a ^4 its chor<J a 1^00

Dialogue III.

^75

The Golden Rule.

^8 9^996 11600

ai6oo

57597600
^5996
191992

, 357^
58 I ^0735 1 13600

333^
42

From this other working the ftar is found to be diftant from the
centre more than 716. femidiameters.

gr. m. gr. fee.

Altitudes ^LW^r. $1 18 j Altitude ^ 7^ 30 00
thcPote pHtfi/^^*^/- 4^ .22 I of the Start 76 33 45

2 56
a 56

gr. m. fee.

("BAD a 56 00 its Chord 5120

Angles DC loi 58 00 ? C 97%

(?BCD o 00 15 r 2 7

The Golden Rule.

7 97845 — ^1^^

5120

1956900

57845
489235

7»5

7 15009! 66400
4

Thefe as you fee are five workings which place the ftar very
JJ^ch above the Moon. And here Idefire you to confidcrupon
^^t^ particular, which even now I told you, namely, that in grcae

M m di-

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2°K.B. 9,163

1-74 G. G A L r L it u s, his Syjleme:

diftanccs, the mutations, or if you pleafe corrcftions , ofavc-'^
ryfew minutes, removeth the ftar a very: great way farther ofFJ
As for example, in the firft of thefe workings , where the calcu?^
lation made the ftar 60. femidia meters remote fiom the centrcJ^
with the Parallax of a. minutes v he that would maintain that it|
was in the Firmament , is to corrcS: in the obfervations but onely
two minutes, nay leffe , for then the Parallax ceafeth, orbc*
commeth fo fmall , that it removeth the ftar to an immenfe di-
ftance , which by all iy received to b^ tti€ Firmament. In the fe-
cond indagation 5 or working , the cbrrefiion of lelTe than 4 ^•
frim, d th the fame. In the ifef d, stnd fourth, like as in the firft?
two minutes onely mount the ftar even above the Firmament.
In the laft preceding, a quarter of a nvi^Aute , that is 15. fecondsj
gives us the fame. But it doth not fo occur in the fublunary alti-
tudes for if you fancy to your felf what diftance you moft
Mfc*, 'ai^id go abtnft to corrcft the workings made by the h^'
thour , and adj.ift them fo as that they all anfwcr in the fam^
determinate diftance 5 you will find how much greater correfli'
c^s they do require.

Sagr. It cannot but help us in our fuller underftanding
Aingsjr to fee f ome ^jxamples of this which you fpeak of.

S A I. v. Do you affign any whatfoever determinate fublunarfi
diftance at plcaiure in which to conftitute the ftar, for with fm^*^
ado we may aflbrtain our felvcs whether corrcftions like to thefei
^hicb we fee do fuffice to reduce it amongft the fixed ftars , wiUl
reduce it to the place by you affigned.

Sagr. To take a diftance that may favour the A utbour ,
will fuppofe it to be that which is the greateft of all thofe foun<J
by him in his 1 2 workings j fbr whilft it is in controverfie bc'
twcen him and Aftronomers , and that they affirm the ftar
have been fuperiour to the Moon, and he that it was inferipuf'
very, fmall fpace that he proveth it to have been lower, givetS
him the viSory.

S A L V. Let us therefore take the feventh working wrought
upon the obfervations of T^ycho and Thaddi€HS Hagecius , W
which the Authour found the ftar to have been diftant from tb^
centre 3a. femidiameters , which fituation is moft favourable
his purpofe and to give him all advantages , let us more^?)^^-^
place it in the diftance moft disfavouring the ^J?r(?»t?;«frj, ^^'hicn
is to fituate it above the Firmament. That therefore being *^P'
pofedjlet us feek in the next place what correSions it would be n*^'
ceffary to apply to his other 1 1 workings. And let us begin at th^
firft calculated upon the obfervations of Hain^elim and Manroit^^^
in whkfe the Authour findeth the diftance from the centre aboa|
3. femidiai^aetcrs with the Parallax of ^gr. 42 m. ^o.fec.

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2°K.B. 9,163

Dialogue Hi.

fee whether by withdrawing it 20. miniates onely > it will rife
to the height of 32. femidiamcters : See the fliort and true opera-
tion. Multiply the fine of the angle BDC, by the fine of the

Uain'z^clhis Pole 48 32

Manrolicus Pole 38 30 ~

9 52

gr. m. f :c.

^ _y6 34 50

— if 62 00 00

14 34 30

9 52 00

Parallax 4 42 30

Angles

582

I 7200

18982000
66437
9491

28
16324]
4688

52000

17100
94910

58:

^chords D, and divide the produft , the five laft figures being cut
off by the line of the Parallax , and the quotient will be 28. fe-
t'^iidiameters , and an half, fo that though you make a corrcftion
4^^«*2 min. 30 fee. taken from 4 ^r. 42 min. 30 fee. it fliall
^ot elevate theftar to the altitude of 32. femidiameters , which
^^rrcftion for Simplictns his underftanding it , is of 262. minueis,
an half.

^0 the fecond operation made upon the obfervations of Hain-
T ' and SfHlernSy with the Parallax of o.^r. Smn. ^ofec.
ftar js found in the height of 15. femidiamcters or therea-

BDC
BCD

Sines

6166
979^7

^^tits , as may be feen in the fubfequent working.
B D Chord

M m 2

97987

z^6

G. G A L I L ^ u his SyflemCf

979^7
6166

58792:

^^79

979^7

24716041 1 87842

II03
II

And bringir^ back the Parallax o gr. 8 m, 30 ftc, to 7 gr.
7 w. whofe fine is 204, the ftar elevateth to 30 femidiametcrs or
thereabouts j therefore the correaion of o ^r. i mi. 20 (cc. doth
not fuffice. * ^

204I6041 ( 87342

Now let us fee what correaion is rcquifite for the third work-
ing made upon the obfervations of Hain^elim and Tycho , which
rendercth the ftar about 19 femidiameters high , with the Pa-
rallax of i oj«. fr, The ufual angles and their fines, andchor
found by the Authour, are thefe next followina • and they re
move the ftar (as alfo in the Authours working) 10 femidi*'
meters from the centre of the Earth. It is neceflkry therefore fo^
the raifiiigof if , to diminifli the Parallax according to the Ruk
which he likewife obferveth in the ninth working. Let us there-
fore fuppofe the Parallax to be 6 m. prim, whofe fine is 1 75 ,
the divifion being made , there is found likewife lefrethan3^
f^idiameters for the ftars diftance. And therefore the corredi-
on of 4 mw. prim, is too little to fervc the Authours purpofe.

Chord 13254
Sine • 4088^
Siiac 2 pi

132^4

lALOGUE.

III.

277

40886

79534
lodoja
10603a
53016

18 . 30
a?! I 5419 1 03044 1 175 1 541 9
250
181

Let us come to the fourth working , and the reft with the fame
^ule, and with the chords and fines found out by the Authour
himfelfj in this the Parallax is 14 w. print, and the height found
hSc than 10 femidiameters , and diminifliing the Parallax from
1 4 min. to 4 mitt, yet nevertheleffc you fee that the ftar doth not
elevate full 3 1 femidiameters. Therefore 1 o mih. in 1 4 min. doth
not fuffice.

CBAD Chord 814a
Angles <B DC Sine 43235
tUCD Sine 407

43335
8142

86470

» 72940

43335
345880

n6|3530 1 19370
4

In the fifth operation of the Authour we have the fines and the
'^hoidas youfee, and the Parallax is o^r. 42 30/ef. which
rcndcrethxhe height of the ftar about 4 femidiameters , andcor-
teaingthc Parallax , with reducing it from ogr. j^r m. fee.
^'^.OS'-- 5 m. onely , doth not fuffice to raifc it to fo much as 28 fe-
"»»diameters , the cotreaion therefore of ogr. 37 w. 30 fee. is
too little.

: CBAD Chord 4034
Angles <B DC Sine 9799^

Ibcd 1336

G. G A L 1 L ^ u s , his Syiieme.

9799'^
4034

293 9P4

1058
3

In the fixth operation the chord , the fines and Parallax arc as
followeth , and the ftar is found to be about 4. femidiameters i
us fee whether it will be reduced , abating the Parallax from 8 f-
to I m. oncly j Here is the operation , and the ftar raifcd but to
37. femidiameters or thereabout ; therefore the corrcdion of 7 1*'
in 8 m. doth not fuffice.

BD Chord ipao

. B D C Sine 40348

BCDS^r. Sine 253

40248
1920

804960
363233

77a I y6i6o
19%

In the eighth operation the chord, the fines, and the FarallaS,
as you fee, are thefe enfuing , and hence the Authour calculate*
the height of the ftar to be i . fcmidiameter and an half, witb*=
ParaUaxof 43. ww. which reduced to i min. yet notwitbftao<^'
ing givcth the ftar leffe remote than 34. femidiameters, tbccorre-
aion therefore of 43. mm, is not enough.

BD Chord 1804

B D C Sine 36643
BCD Sine

36643

Dialogue. IIL

i8oi|
393144

29 1 66t 1 03972
8|

i75ji

Let us now fee the ninth. Here is the chord , the fines and
Jne Parallax which is 1 5 m. From whence the Authour calcu-
*^tes the diftance of the ftar from the fupcrficies of the Earth
^ be leffe than a'^fcven and fortieth part of a femidiameter , *Hefe the La-
this is an errour in the calcultaion , for it cometh forth truly, tmevcrfioniserro-
^^vvefliall fee here below, more than a fifth : See here the quo- TZ^^r^M
^^nr 13 ^ y which h more than one fifth. &c. '

B D
BD C
BCD

Chord

Sine

232
39046
436

39046
232

78092
117138
78092

436 I 9Q I 58672

That which the Authour prcfently after fubjoyns in way of
the obfcrvations , that is , that it fufliccth not to re-
^^ce the difference of Parallax , neither to a minute , nor yet
^ y^^ eighth part of a minute is true. But I fay , that neither
^ ^ the tenth part of a minute reduce the height of the ftar td
3^-f^midiameters j for the fine of the tenth part of a minute,
^t IS q(q^ fecondsjis 3 , by which if we according to our Rule
j^^uld divide 90. or we may fay , if we (hould divide 9058672.
than^^°^^* the quotient will be 30,11411, that is little more
3Q« femidiameters and an half.

J. The tenth giveth the altitude of the ftar one fifth of afemi-
^"^eter, with thefe angles, fines, and Parallax, that is, 4 ^r.

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

G. Galil^us^ his Syjieme.

m. which I fee that being reduced from 4 gr. 30 min. to a min-
yet ncverthelcffe it elevates not the ftar to 29. femidia meters.

BD
BDC

BC D4gr. 30 m.

Chord

Sine
Sine

1746

7846

93050
17460

553300
36830
^4435

58 \ 1607 I ^93°^
441
4

The eleventh rendereth the ftar to the Authour remote abou^
13. fcmidiameters , with the Parallax of t^s^.imn, let us fee, r^'
ducing it to 3 o win, whether it will exalt the ftar : See here th^
calculation elevates it to little leffethan 33. femidiameters ,
correflion therefore is little lefle than 35, min, in 55. min.

BD Chord 19748

BDC Sine 96 1 66

BCD o ^r. 55 Sine 1600

96166
19748

639338
384664
673163
865494
96166

58:

5<5i68

The twelfth with the Parallax of i. ^r. ^6. min.

fliakethth^

ftar leffe high than 6. femidiameters , reducing the Paralla?^
3o Win, it carricth the ftar to IcfTe than 30. femidiameters
Itancc 5 therefore thecorreftion of i er. 16. w«. fuflSceth not-

Dialogue III.

Bt) Chord 172$^

BDC Sine 96150

BCD tgr. 36 w.Sine 2793

17258
96150

862900
17258
103548
,55322

582

16593

56700

4957

Thefe are the CorreBhns of the Parallaxes
of the ten wordings of the Anthor, to
reduce the Star to the altitude of
32 Setftidtameterf.

fee.

gr. m. fee.

04 22 30 ^ —

oo o/^ 00 -

00 lo 00 — -

00 37 00

00 07 00

Oo 42 00 .

00 14 50

a8 00

m 04 4a 30

in 00 10 00

in 00 14 00

in 00 42 30

in 00 18 00

in 00 43 00

in 00 15 00

in 04 30 00

in 00 55 00

in oi 36 00

^roin bcnee we fee^ that to reduce the Star to 32. Semidiame-
^^ersjn altitude, it is requifite from the fum of the Parallaxes 836.

^^f^btraa75<^. and to reduce them to 80. nor yet doth that
fufficc.

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

28 2.

G. G A L I L ^ u s , ]m Sjfunie.
we fee alfo, (as I have rioted even now) that fliouM the

Authour conlent to affign the diftance of 32. Semidiamcters for
the true height of the Star, the corredion of thofe his 1 o. workings;
(I fay 10. becaufethe Itcond being very high, is reduced to the
height of 32. Semidiameters, with a. minutes correaion) 30 make
them all to reftore the faid Star to that diftance^would require fuch
areduflionof Parallaxes, that amongft the whole number of fub-
ftra£}ions they fliould make more than 756 ;?r. whereas in the
5. calculated by me, which do place the Star above the Moon, to
correft them in fuch fort, as to confiitute it in the Firmament,
the correaion onely of 1 o. minutes, and one fourth fufficeth.

Now adde to thcfc, other 5. workings, that place the Star pre-
cifcly in the Firmament, without need of any corredion at all,
and we lhall have ten workings or indagaiions that agree to place
it in the Firmament, with the correaion onely of of them (r^
hath been feen) but 10 ;;.. and 1 5 fee. Whereas for the correfii-
on of thofe 10. of the Authour, to reduce them to the altitude of
32. iemidiamcters, there will need the emendations of 7;; 6 mi-
nutes in 836. that IS, there muft from the fumme 836 be fubftra-
fted 75(5. if you would have the Star elevated to the altitude of
32. femidiameters, and yet that correftion doth not fully ferve
The workings that immediately without any correaion free t
Star from Parallaxes, and therefore place it in the Firmament
and that alfo in the remoteft parts of it, and in a word a. hid
as the Pole it felf, are thefe 5, noted here. ' ^

fThIIZ^^^^^ W I Altit.of the Star {^^

gr. m.

Akit.of theStar{7^
7^ 34

ir. m.

4 4

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

I ALO®UE.

Ill

Keinhold.

51 »

gr. m.

79 30

a 56

gr. ^r. Mr.

Earner ar ? J<2 ^4. t I'

W^^ec/i^SP^l^^ J I Alt;t.of theStar^^^ ^[

Of the remaining combinations that might be made of the Ob-
prvations of all thefe Aftronomers, thofe that make the Stars fub-
^tne to an infinite diftance, are many in number, namely, about
30- more than thofe who give the Star, by calculation, to be be-
low the Moon i and becaufe (as it was agreed npon between us) it

to be believed that the Obi'ervators have erred rather little than
^Uch, it is a manifeft thing that the correSions to be applied to
the Obfervaations, which make the ftar of an infinite altitude, to
reduce it lower, do fooncr, and with lelTer amendment place it in
Ae Firmament, than beneath the Moon ^ fo that all thefe applaud
the opinion of thofe who put it amongft the tixed Stars. You may
^dde, that the corrcftions required tor thofe emendations , arc
J^l^ch leffer than thofe, by which the Scar from an unlikely pro^i-
^^ty may be removed to the height more favourable for this Au-
^ur, as by the foregoing examples hath been feen , amongft
^hichimpoflible proximities, there are three that feem to remove
^neStar from the Earths centre,, a leffe diftance than one Semidi-
^nieter, making it, as it were, to turn round under ground, and
^^^fe are thofe combinations, wherein the Polar altitude of one
.^f the Obfervators being greater than the Polar altitude of the
P^^^r^ the elevation of the Stat taken by the Hrft,is leffer than the
^?^ion of the Star taken by the latter.

The firft of thefe is this of the LarrdgYa^^e with Gemma,
^here the Polar altitude of the Landgrave 51 gr- 18 win. is
l^^^ter than the Polar altitude of Gemma, which is 50 ^r. 50 i»,
^"^^he altitude of the Star of the Landgrave J9gr. ^omiti,
*'^^ff^r than that ofthe Star, of Gemma 79&^- f S ^'^'

gr. m. '"'^ gr.

GSr'l-'oU.al.ic.^^; I AUU.otd,cSur{7',

N'n a

tft.

The

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

G. Galil^us^ his Sjflme.

The other two are thefc below.

Keinholdus. K^, . ... , ^ci i8

Gemma.

Polar Altitude;^* ^^Altit. of theStarJ^^ ^

Fromwhat I have hitherto demonftratcd, you may gucffc how
muth this firft way of finding out the diftance of the Star, and
proving it fublunary introduced by the Authour, maketh againft
himfelf, and how much more probably and clearly the diftancc
tfceftctfis tolkaed tohavebreenamongft the more remote fixed
Stalls.

S^iwfX^ A^t^ this particular, 1 think that the mefficacy of th^
Altthors'demonftrations is very plainly difcoveredjBut I fee that all
this was ccwnpr ifed iivbutra few leaves of his Book, and it may b^?
that fi^tiift otto bfM^ Argum^ts are more conclufive then the^^

* S xlt^^v'^Rithet' they tifmft^c^ds be !efie valid, if we will tak^^
thofe tfeat lead tte way for a pro^of 6f the \th : For (as it is clear)
thei*i<i^r^ii«,ty and i nconclii fluent (Te of thofe, is manifeftly ob-
ferveflctd dfeviie k-y^^^^^ committed in the inftra-

meiita! 6bletvatiorts3 upon wh^di rftt Polar Altitude and heighc
of %htpr wais tfe>ught td have b^en ?uftly taken ' all in efFe5
h^viri^l^afify ert^V- Ahd ytr to find tire Altitude of the Pole>
ftroncfiWcrs have had Ages of time to apply themfelvcs to it, at ih^^
feafet^ :'^nd the Meridian AltituA^s of the Star are eafier to
t^bfef^d^^^sbeittg i^fft^ and yielding the Obfervatof

fome tittle t6 coi^i^^jifue the famfr,in regard they change not fenliblyj
\vi a (hort tttoe^as thWe do that arc remote from the Meridian, h^^
if thi^beffe^s it i^itifoft certaiYi; what credit fliall we give to Calcu-
lations fou-nded ^u^^o^n Obfevations more nifmerous, more difficult
to be wrought, more momentary in vadation, and we may aJ^^
with tnftriiments more incommodious and erronepuft ? Up^^ ^
Jlight p^(iTaI of thc: cnfuing demonfrrations, I fee that the
putations'are made upon Altitudes of the Star taken in diflfe^^^^

VerticalCirdes, which are called by theArabick name,/^z,/>^«^'^'^>^
is moveable inftruments arc made ufe of, notoif

V , ^ - , -

which ob fer va I ions

ly in th^ Vertical'Circles, but in the Horizon aIfo,at the fame time i
inioinuih that it is requifite in the fame moment that the ahitu^I^^
IS taken, tahawc bbfei:ved,in tjie Horizoft, the diftance of the Vir;

Dialogue III.

tical point in which the Star is , from the Meridian Moreover,
^feet a contiderable interval of time , the operation muft be re-
peated, and exaft account kept of the time that palTed, trufting
eitlier to Dials,or to other obfcrvations of the Stars. Such an Olio
of Obfcrvations doth he fet before you , comparing them with
f<*ch another made by another obferver in another place with a-
t^othcr different inftrument, and at another time i and from this
tlie Aiithour leeks to coUeft what would havebeen.the Elevations
of the Star, and Horizontal Latitudes happened in the time and
hour of the other firft obfervations,and upon fuch a coaequatioa he
in the end grounds his account.Now 1 refer it to you, what credit
is to be given to that which is deduced from fuch like workings.
Moreover J doubt not in the leaft, but that if any one would tor-
ture himfelf with fuch tedious computations, he would find, as in
Aofe aforegoing, that there were more that would favour thead-
^^fe party ^ihan the Authour : But I think it not worth the while
to take fo much pairts iti a thing, which is not,amongft thofe prima-
ry ones^by us underftood. - . ,. , ^
^ ' S A G R 1 am of your Opinianin this particular : But this bufi-
i^ffe bein^ environed with fo many intricacies, uncertainties,ana
mours,Mp''on what confide^jce have fo many Aftronomers pofitivc
ly pronounced the new Star to have been fo high >
f!: S A L V. Upon two forts of obfcrvations moft plain, moft eafic,
^nd moft certainjone only of which is more than fuflScient to affure
uj?^ that it was fcituate in the Firmament^ or at leaft by a great
<liftanGe fuperiour to the Moon. One of which is taken from the
equality, or little diffcnng ine^quality of ica diftances Irom the
^oie, afwpUvvhilft it^wtis in the loweftparrof the Meridian, as
^f^^n it wa^in the upper mofc : , i The other isdts having perpetual-

kept the fauje diftancas from certain of the fixed Stars,ad>acent
^it, and particularlylfi^ti the eleventh of Qaffiopea ,^ no more
remote from It than one degreeapd an half ^ from which two par.
Oculars is undoubtedly inferred^either the abfolute want of ParaU
l^x, or fu.h a fmalneffe thereof, that it doth ^affure^ us with very
^^Ptditious Galculations of its great diftance from t^^^^^f^'

S A o r; But thefe things, were they not known to this Author,
^^if he;fiw them, what doth he fay unto them >

We are wont to fay, of one that havn^g
«^Wet6 coverhis fault, producethfrrvolousexcufes,^^

^^^v4r>butthis Authour runs,not to the Cords, but to the Spi-
ders Wlk T o Hiall plainly Ibe in our examination
^rs vv«b QtHeaven j you inaii piaun^ ^k^^ ...kvu
^fthefe cwo-particul^s even now h.nted. And firft, that wh.ch
ft^Nvcth us thc Polar dUlancesof the Obfervitorsone by one I
twtye noted down in tfeefe brief Calcubtioni4 atullnndej-
3 1 T ftancr-

285

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

G. G A L I L u s. Ins Sylieme.

ftanding of which, I ought firft to advcrtife you, that when ever
the new Star, or other Phacnomcnoa is near to the earth, turning
with a Diurnal motion about the Pole, it will Teem to be farther
off from the faid Pole, whilft it is in the lower part of the Meridi-
an, then whilft it is above, as in this Figure [being jig. third tf
this Dial.'] may be feen. In which the point T. denotes thecefl"
tre of the Earth ; O. th.- place of the Obfervator ; the Arch VPC
the Firmament i P. the Pole. The Phenomenon, [or appearance']
moving along the Circle F S. is feen one while under tlic Pole by
the Ray O F C. and another while above, according to the Ray

0 S D. fo that the places feen in the Firmament are D. and C-but
^etrue places in refpeft of the Centre T, are B, and A, equidi-
ftant from the Pole. Where it is manifeft that the apparent place
ot the Fhenomenon S,that is the point D, is nearer to the Pole than
the other apparent place C, feen along the Line or Ray OPC
which ,s the firft thing to be noted. I„ the iecond place you ffloft
note that the cxces of the apparent inferiour diftance from thePofe
over and above the apparent fuperiour diftance from the faid Pole '
IS greater than the Inferiour Parallax of the Phenomenon, that is, I
lay, that the cxcefTe of the Arch C P, (the apparent itiferior</'-
ftance) over and above the Arch PD, (the apparent fuperiotdi-
ftancc) is greater then the Arch C A, (th^t is the inferiour Paf»-
lax.) Which is eafily proved V for the ArchC P. morecxceedf*
P p, then P B i P B, being bigger than P D, bat P D. is equal to
^A, andtheexceffeot C P, above PA, is the arch C A there-
fore the exceflb of che a.U CP above\he arch P H great'
er than the arch C A , which h the parallax of the PhLnonfeno.
placed ,n F , which was to be demonftrated. And to aive all Z^'
vantages to the Author , let us luppofc that the pa"^^^^^^^^^^^^^

in F , IS the whole exceffe of the arch C P (that is of the inferioit
diftance from the pole ) above the arch P D (the inferiour di-
ftance.) I proceed in the next place to examine that which
oblcrvations of all Aftronomers cited by the Authour giveth
amongft which , there is not one that maketh not againlt himfe^
and Ins purpofe And let us begin with thefeof Bufchii^, wh"
findeth the ftars diftance from the pole,when it was fuperiour,to be
28 gr. torn, and the inferiour to be xS^r, 3o«,. fathat thce^'
celTe IS o gr. oo m. which let us take (in favour of the Author)
li It all were die parallax of the ftar in F , that is the angle Tf C>.

1 hen the diftance from the Vertex [or Zenith] that t ti"^ a^ch
iTn ^ 'Af^^'"/?'*" Thefe two things being found prolong (be

neco, and from it let fall the perpendicular T I and let

Zdt^?V'':'^^^70l, of which the angle I i. r'ight angU,

the diftan"! i r ' ^ '^'^'"g V"""' to the angle V O

tbc diltance of the ftar from the Vertex, Moreover in the triangle

TIf'

I A L O G U E

III.

^ i r, vvliich is alto rectangular , there is known the angle F, ta-
ken by the parallax. Then note in feme place apart the two an-
gles I OT and I FT, and. of them cake the fines, which are
W fet down to tiicni , as you feen. Andbecaufe in the triangle
Jot, the fine T I is 92276. of thofe parts, whereof the whole
^if^e TO is IOOO0O-, and moreover in the triangle I F Tjthe fine T I
is $82. of thole parts , whereof the whole fine T F is 100000, to
find how many TF is of thofe parts, whereof T O is 100000;
we will fay by the Rule of three : If T I be 582. T F is an
iooooo. but if T I vvere 92276. how much would T F be.
Let us multiply 92276. by iooooo. and the produft will be
9227600000. and this muft be divided by 582. and the quotient
Will be 15854982. and fo many (hall there be in T.F of thofe
parts, of which there arc in T O an iooooo. So that if it were
acquired to know how many lines T O, are in T F , we would
divide 15854982 by iooooo. and there will come forth 158. and
^^ry near an half ^ and fo many diameters fliall be the diftance
^ the ftar F ^ from the centre T , and to abrcviate the opera-
tion , We feeing, that the produ^ of the multiplication of 92276.

iooooo , ought to be divided firft by 582 , and then the quo-
^nt of that divifion by iooooo. we may without multiplying
92276. by iooooo. and with one onely divifion of the fine
92276. by the fine 582. foon obtain the fame folution, as may
be feen there below j where 91276. divided by 582. giveth us th«
faid 1 58 1 , or thereabouts. Let us bear in mind therefore , that
the onely divifion of the fine T I , as the fine of the angle T O I

the fine T 1 , as the fine of the angle I F T , giveth us the di-
ftance fought T F , in fo many diameters T O.

Angles-

581

>lOT
>IFT

TF T I

10000 9237^
158^4983

58a j p22j6000OO

3407003746

49297867
325414

922 7-5

582

T F

IOOOOO 1 1 $8 I $4982

«58

582 1 92276
34070
493
3

^87

Sec

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

G. G A L I L ^ u s , his Sjlleme.

See next that which the obfervations of Pencerm givethus^in
which the inferioLir diftance from the Pole ts 28 gr, 2 1 m. and the
fiipcriour 28 ^r. 2 m. the difference o gr.i^ m. and the diftance
from the vertical point 66 gr. m, from which particulars is ga-
thered the ftars diftance from the centre almolb 166 femedia-
meters.

Angles <i£c

66
o

Sines

> 553

^■^5-W
553 I 91672

363P7
31a

Here take what tycho his obfervation holdeth forth to us , in-
terpreted with greateft favour to the adverfary ; to wit, the infefi'
our diftance from the pole is i%gr. 1 3 m. and thefuperiour aS/^
a »/. omitting the difference which iso^r. 1 1 w. as if all wereo^j
Parallax i the diftance from the vertical point (Sa^r. 15 m. Bc/><>'^
here below the operation , and the diftance of the ftar fromtl^
centre found to be 976,1 femidiameters.

Angles

?IAC
5IEC

gf- m.

320 I 88500
3418
I

The obfervation of Keinholdm^ which is the next cnfuing^g'*^'
cth us the diftance of the Star from the Centre 702. Scm&^'
meters.

ii6\ 92016
10888
33

•

Dialogue III.

From the following obfervation of the Landgrave^ the diftance
of the Star from the Centre is made to be 1057 , Semidiameters.

^ 1 5*^^

Sines

87 192012
5663

Two of the moft favourable obfervations for the Authour be-
'ng taken from Camerarins, the diftai.cc of the Star from the Cen-
tre is found to be 3143 Semidiameters.

Angles<j J. ^

3H3
4295

The Obfervation of Uunofim giveth no f araUax , and there-
fore tendreth the new Star amongft the higheft of the fixed. That
nain-x.eliHs makes it infinitely remote, but with the corredion
of an half min. prim, placeth it amongft the fixed Stars. And the
fame is collefted from 'Vrfinits,v/'nli the correaion of 1 2. min.prim.
The other Aftronomers have not given us the diftance above and
Mow the Pole, lo that nothing can be concluded from them. By
*>s time you fec,that all the obfervations of all thefe men confp.re
^^gainft the Author, in placing the Star in tffe Heavenly and high-

S IT^Xnt what defence hath he for himfelf againft fo manifeft

•^ontradi^ions > > , j . • l

, Sai.,. He betakes himfclf to one of thofe weak threads which

^ fpeakof^faying that theP.r.K.x,. come to be leffened by means
«f ^I'erefraaions, which opperating -""-"'y^"^'""f:£: ff"-
^'"«'«o«, whereas the vZuaxes abafe it ^ow of what little
^^^^ thie lamentable refuge is,judge by this,that m cafe that effedof
the refractions were of fuch an efficacy, as that which not long time

r Aftronomers have introduced, the moft that they could
hine the elevating a Tkeuomenon above the Horizon
Oo rnotc

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

G. G A L I L ^ u his Syjlcmc.

more than truth, when it is before hand 2 3. or 24. Degrees higfr,
Would be the Icflenihg its Tarallax about 3. minutes, the which
abatemiefit is too fmall to pull down the Star below the Moon, an<l
in fomt cafes is lelTe than the advantage given him by us in admit-
ting that the cxcefTe of the inferiour diftance from the Pole above
the Superiour,is all Parallax^ the which advantage is far more clear
and palpable than the effeft of Rcfiafion, of the greatnefle of
which I ftand in doubt, and not without reafon. But befides, I
demand of the Author, whether he thinks that thofe AftronomerSj
of whofe obfervations he maketh ufe, had knowledge of thefe ef-
icSts of Refradions, and confidered the fame, or no j if they die!
know and conlider them, it is leafonable to think that the,kept ac-
count of them in afligning the true Elevation of the Star, making
in thofe degrees of Altitude dil'covered with the hiftruments, fuch
abatements as were convenient on the account of the alteration^
made by the Refraftions ; infomuch that the diftances by thea?^^'
hvered, were in the end thofe corrected and exaft, and not the ap-
parent andfalle ones. But if he think that thofe Authors m^^^
no reflexion upon the faid Refradions, it muft be contcffed, tb*^
they had in like manner erred in determinmg all thofe things ^^^^
cannot be pcrfedly adjufted without allowance for the ReftaS^'
ons i amongft which things one is the precife inveftigation of t*!^
Polar Altitudes, which are commonly taken fiom the twoMeri^''
an Altitudes of fomc of the fixed Stars that arc conftantly vifibl^J
which Altitudes will come to be altered by Refradion in the fai^^^
manner, ,uft as thofe of the hew Stars fo that the Polar Altifd^
that is deduced from chein, will pfovc to be defeftive and to paf
jale of the lelf fame want which this Author affigns to the h\^\
tudes afcribed to the new Star, to wit, both that and thefe
ht with equal falfliood placed higher than really they are. Butat^J
fuch errpur, as far as concerns our prefent bufinefTe, doth no p^^'
judce at all : For we not needing to know any more, but on^'/
the difference bctwe^ the two diftances of the new Star from*
t»6le at fuch time as it was inferiour and fuperiour,it is evident tb^^
.^uch diftances would be the fame, taking the alteration of Re^*'
diion commonly for the Star and for the Pole, or for them wb^^
comiiionly amended. The Authors Argument would i

ndeedfcf^

had fomc ftrength , though very fmall, if he had aflured i^^^^^
the Altitude of the Pole had been once precifely afligned, a^rd cor-
rcae'd from the errour depending on refraftion, from "^^^ \
gain the Aftronomers had not kept them felves in affigning
titudes of the new Star but he hath not afcertained us of
'^^' I*^^^^^ he have done, nor haply, (and this is taor^ ^^'

^ was that caution wanting in the Obfervators.
b A G R. This argument is in my judgment fufficiently anftv^'

I A L O G U E

2^1

ed j therefore tell me how hedil-ingagcth himfelf in the next place
■ffom that particular of the Scars having conftantly kept the fame
diftance from the fixed Stars circumjacent to it.

S A L V. He betakes himfelf, in like manner, to two threads, yet
more unable to uphold him than the former : one of which is like-
wife faftencd to refraction, but fo much lefs firmly, in that he
faith, that refraftion operating upon the new Star, and fublimating
it higher than its true fituation, makcth the feeming diftances un-
tain to be diftinguiflied from the true, when compared to the cir-
cumpofed fixed Stars that environ it. Nor can I fufficiently ad-
n^ife how he can diffemble his knowing how that the fanie refra-
Q^ion will work alike upon the new Star, as upon the antient one

neighbour, elevating both equally, fo as that fuch a like acci-
dent altereth not the fpace betwixt them. His other fubterfuge is
yet more unhappy, and carryeth with it much of ridiculous, it bt-
ing founded upon the crrour that may arifc in the inftrumen talo-
perationit felf i whilft that the Obfervator not being able to
conftitute the centre of the eyes pupil in the centre of the ScjC-
fant(anInftrumentimploycdin obferving the diftance between
two Stars) but holding it elevated above that centre, as much as
the faid pupil is diftant from I know not what bone of the cheek,
againft which the end of the Inftrument rcfteth, there is formed
in the eye an angle more acute than that which is made by the fides
of the Inftrument ^ which angle of raycs difFereth alfo from it
fclf , at fuch time as a man looketh upon Stars, not much elevated
above the Horizon, and the fame being afterwards placed at at
great height ^ that angle, faith he, is made different, while the In-
ftrument goeth afcending, the head ftanding ftill : but if in moun-
ting the Inftrument, the neck fliould bend backwards, and the
head go rifing, together with the Inftrument, the angle would then
Continue the fame. So that the Authours anfwer fuppofeth that
^lie Obfcrvators in ufing the Inftrument have not raifed the head,
^5 they ought to have done i a thing which hath nothing of likcli-
*^Qod in it. But granting that fo it had been, I leave you to judge
^hat difference can be between two acute angles of two equicru-
triangles, the fides of one of which triangles are each four
llt^lian-] Braces [i.e. about three Englifli yards] and thofe of the
^^her, four braces within the quantity of the diameter of a Pea ;
7 the differences cannot be abfolutely greater between the length
^^^hetwovifiverayes, whilft the line is drawn perpendicularly
trom the centre of the pupil, upon the plain of the Rule of the
Sextant (which line is no bigger than the breath of the thumb)
^nd the length of the fame rayes, whilft elevating the Sextant,
^ithout raifing the head together with it, that fame line no longer
^lleth perpendicularly upon the faid plane, but incUneth, making

OO 2 tht

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2°K.B. 9,163

1C)Z

' Tr2«:;'-iirdi.

G. G A L I L ^ u s, his Syjlcme.

the angle towaids the ekxumferencc lomcthing acute. But wholly
to free this Auchour from thetc unhapp^^ lies, let him know, (m re-
gard it appears that he is not very skilful in the ule of Aftronomi'
call Inftruments) that in the fides of the Sextant or au^drant
there are placed two * Sights, one in the centre, and the other at
the other at the oppofite end, which are raifcd an inch or more a-
bovc the plane of the Rule and through the tops of thole fights
the ray of the eyeismade to paffe, which eje like wife is held an
hands breadth or two, or it may be more, f om the Inftrument^
that neither the pupil, nor any bone of the cheek, nor of the W'boie
body toucheth or itayeth ic felf upon the Inftrumcnt, nor flinch
leffe h the Inftrument upheld or mounted in the armes, efpecialiy
if it be one ofthole great ones, as is uiual, which weighing tensj
hundreds, and alio thoufands of pounds, arc placed upon very
ftrong feet or frames : fo that the whole objeftion vaniflietl''
Thele are the lubtei fuges of this Authour,which, though they W^^^
all of ileel, would not lecure him the hundredth part of a minut^'
and with thefe he conceits to make us believe, that he hath coi^*j
penfated that djiference, which importech more than an hundf^
minutes ^ 1 mean, that of the not obferving a notable differen^
in the distances between one of the fixed ttars, and the new
in any of their circulations ^ which, had it been neer to the Mo^>^>
it ought to have l?ecn very <;6nfpicuous to the meer fight, with^' .
any Inftrument, efpecialiy comparing it with the eleventh of
fiopcidy its neighbour, within i gr. 30 m. which ought to have ^
ricd from it more than two diameters of the moon, as the niot^
intelligent Aftronomers of thofe times do well note.

S A G R. Methinks 1 fee th^t unfortunate Husbandman, who ar
tcr all his expefted crops,have been beaten down anddeftroyed W
a ftorm? ,goeth up and down with a languifliing and down-c^^
look,, gleaning up every fmatl ear that would not fuffice to keep
chicken alive one fole day. j
S L V. Truly, this Authour came out too flenderly pr<>^^^j
with armes againft the affailants of the Heavens inalterability'
with too brittle a chain attempted to pull down the new
Cajpopeia from the higheft Regions, to thefe fo low and elemen^
ry. And for that 1 think that we have fufficiently demonftf^^^^
the vaft difference that is between the arguments of thofe A
nomers, and of this their Antagonift, it will be convenient f'^^^j^.^^jj
leave this particular, and return to our principal matter
there pr^fents it felf to our confideration the annual moti^>J^ ^^^j^
n^only afcribcd to the Sun, but by Ari^iarchus Samins fivft ^ .
and after by Copernicm taken from the Sun, and transferred ^P^^
the Earth ,againft which Hypothefis, methinks I fee Sim/^^^^^^i,
come ftr94^gly provided, and particularly with the fword

I ALOGUE.

IIL

Wkler of the little Treatife of Contlnfions, or Difquifitions Ma-
th^^^matical, the oppugnations of which it would be good to be-
gin to produce. , /> i r
S I i^V. I will, if you fo pleafc, refer ve them to the laft, as thole

are of lateft invention.
S A L V. It will therefore be necclfary) that in conformity to the
method hitherto ohferved, you do orderly, one- by one, propound
t)ie arguments, on' the contrary, afwell of Anfioth, 2.s of the o-
ther ancients, which (hall be my task alfo, that fo nothing may e-
fcape our ftrift confideration and examination and likcwifc Sa-
grUm, with the vivacity of his wit, fliall interpole his thoughts, as
he ftiall finde himfelf inclined.

S A G R. I will do it w:ith my wonted frcedome j and your cona-
mauds ftall oblige you to excule me ia fo doing.

Sal v. The favour will challenge thanks, and not an excufe.
But now let Simplicity begin to propofe thofe doubts which dif-
fV^de him from belie^^^^ that the Earth, in like manner, as the
9ther planets, may move round about a fixed centre.

"Si m^p The firft and greateft difficulty is tlie repugnance and
incompatibiUtythac is between being in the centre, aiiahqng tar
ftomif- fe'rif theTerreftri^iqiobeweretp move m a year by
the circumference C|f a circle, that is, under the Zodiack, it isim-
poffible that it (hould, at the fame time, be in the centre of the
diack but that the Earth is in the faid centre .Ari^ot\e, Ftolomy,
-ind others have inany wayes proved. .11

Sal V, -toil very well argue, aud there is no queftion but that
one that would make t^jie Earth to move in the circumference of
circle^ mull firft of neceifity prove, that it is not in the centre of
that fame circle Tit now followeth, that we enquire, whether the
^Earth be, or be not in that centre, about which, I fay, thatit tur-
neth, and Vou fay. that it is fixed ; and before we fpcak of this, it
Vlikewife necefllry that we declare our felyes, whether you and I
We both the fame conceit of this centre, or no. Therefore tell
J^^e, what and where is this your intended centre > . , „ .

Simp. When I fpeak of the centre, I mean that ot the Um-
^^ife, that of the World, that of the Starry Sphere.

Sa.v. AlthouPhl might very rationally put it lndirpute,whe.
ther there be any itich centre in liature, or no ^ being that nucher
you nor any one elle hath ever proved, whether the World be fi-
^'^e and fi/urate, or eUe infinite and interminate ^ yet neverthelefs
granting fou,for the prefent, that it is finite, and of a termmate
Spherical Fiaure, and that thereupon it hath its centre *, it will be
.requifite toYee how credible it is that the Earth, and not rat^^er
fome other body ^oth poffeffe the faid cent;re.

I M r. That the world is finite, terminate, and fpheripal, Art"

potle

It hath not hsen
hitherto proved
Any , whether the
Wo U be pitkt or

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

^^4 G. O A L 1 1 ^ u s , Sjffeme.

ftotlc proveth with an hundred demonftiations.
S ■« I ,r All .<Tk:>-k :„ .1 J •

..^ i^.i/vecn wicn an Hundred demonftiations.
S'TtX ^' ^ ^ AH which in the end are reduced to one alone, and that
/. .h., ,hc "O"'^ ' for 'f I deny his afllimption, to wit, that the

^"'T^' rfj'/' '''moveable, all his demonftrations come to nothing, for

Z;-/:!-n ^^.^--'y P'^-^^ the Univerfc to be finite and terminate, foftbat
rt IS moveable. But that we may not multiply difputes, let it be
granted for once, that the World is finite, fpherical, and hath
Its centre. And feeing that that centre and figure is argued from
Its mobility , it will,without doubt, be very reafonable, iffrom the
Circular motions of mundane bodies we proceed to the particular
/nftotIc«,i„ inveftigation of that centres proper place : Nay ^rift J. hitnfelf
thM fotm ta be the - hath argued and determine^l in tk„ r ■' ■^"r"--" , .

c,y.,recf,he u„i. r._ '^"^^'n^d 'u the fame manner, making that

verfcabmt M , ^.^/^ °^ ^l^^ ccnttc of thc Univerfc about which all the Cffk'

//Anltotlc „cre his difoofurP anri «r^<.r^f !k rt "'^'^ altCt m part tbU

M,. ^^''P°7 order of the Univerfe, and confefle himfelf t"

profof,. ftave been deceived in one of thefe two propofuions namel v,
umihM maha. xhet in Dlarincr ir,..»u : L ' i'"'"»""!> , namely)

i^i>inisdcan„,, /> I the Earth in the centre, or in faying , that the

^"'^ Spheres do move about that centre, which tf thct*"

confeirions think you would he choofe?

fift'"'* ' ^^^'^^^ ' '^^O^ou\d fo fallout, the Fcrifi^''

fjjl) \ P*'-ip'>*etichs, I demand of Jriftoti'^

obVriit^ie^^^^ would reply , thiy, ^^

ret uic to fee them , that they might not he > nay, wuu
Th^tn, and wouldfay thattL W:r7ttli%:^'':t^
^.d not as nature will have it , for depriving tht-^fthT£ld
of his Au^ority, with what do you think they would appear in

felf luTdLirthTc!"'"'" ^^"^^•^ ^'m^"^""

whkh of 'rhTL''" ^'^'^ ''"'^ ' I know not how to rcfolv^
S . , A nnT '"^''r ^ft^-m-d the lelTer.
S A L V Apply not I pray you this term of inconvenience to »

. nSce^E^^^^^^^ Itwrarinconv.^-
' ence to place the Earth in thc centre of the Coelcftial revoluti""''

I ? '° * of grc^'f udgment Jet us cxa«uo<=
Kht ^Xr'T." - --1,'and^^^^^^^^^^

difWe frif 1 r '''T^- ^'^^ffi""ing therefore out

^^r"" r/"PP°^"^"'''he|ood liking

notice beyond the fixed ftars) as being of a fpherical

figure;

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

Dialogue. III.

figure
its

and moveth circularly , hath neceffarily, and in rcfpeft of
^figure a centre , and we being moreover certain, that within
^neftarry Sph ere there are many Orbs 5 the one within another,
^ith their ftars ^ which likewile do move circulary , it is in difpute
whether it is moft reafonable to believe and to fay that thcfe con-
teined Orbs do iHove round the faid centre of the World , or elfc
ihout feme other centre far remote from that > Tell me now Sim-
V^tciiis what you think concerning this particular.

Simp. If could ftay upon this onely fuppofition , and that
We were fu^e that we might encounter nothing elfe that might di-
urbus^ I would fay that it were much more reafonable to af-
^rni that the Orb containing., and the parts contained, do all
i^^ove about one common centre , than about divers.

S A L V. Now if it were true that the centre of the World is the
about which the Orbs of mundane bodies , that is to fay, of
tnc Planets , move , it is moft certain that it is not the Earth , but
the Sun rather that is fixed in the centre of the World. vSo that as
t'^is firft fimplc and general apprehenfion , the middle place
»^elongeth to the Sun , and the Earth is as far remote from the
centre, as it is from that fame Sun.

S I M p. But from whence do you argue that not the Earth, but
the Sun is in the centre of the Planetary revolutions }

Salv. 1 infer the fame from moft evident, and therefore ne-
ceflarily concludent obfervations , of which the moft palpable to
<^xclude the Earth from the faid centre , and to place the Sun
herein , are, the feeing all the Planets one while neerer and ano-
ther while farther off from the Earth with fo great differences, that
example , Venus when it is at the fartheft , is fix times more
remote from us , than when it is neereft , and Mars rifeth almoft
^g"t times as high at one time as at another. See therefore whc-
ArifiotU was not fomewhat miftaken in thinking that 4. was
^t all times equidiftant from us.

S I M F. What in the next place arc the tokens, that their moti-
ons are about the Sun ?

Salv. It is argued in the three fupcriour planets Mars^ J^pi'
and Saturn , in that we find them alwayes neereft to the
when they are in oppolition to the Sun , and fartheft off
^hen they are towards the con^unftion, and this approximatiaa
^nd receflion importeth thus much that Mars neer at hand , ap-
P^J^reth Very neer 60 times greater than when it is remote. As to
in the next place , and to Mercury , we are certain that
y devolve about the Sun, in that they never move far from
, and in that we lee them one while above and another while
elow It , as the mutations of figure in Ventis neceflarily argueth.
lonchiug the Moon it is certain , that (he canDiot in any vray

fc«

Its m'Jre ration
nAl that tht Ork
cautetnings and tht
pdrts coHttttiedyda
mone 4II €bom ont
centre , than ttven
divers.

If the centre of
the '-^orld he the
(.ime vftrh that a*
haftt vfh ch the pia*
neti m»ve^ the 5«»
and *ior the Earth
is f laced in it.

Obfervations from

^ence tt ts

col-

teHred tbdt the Sftm
and not the Esrth
ts in the centre of
the Celefifdl r*vo'
Imioasn

Tht mtitdtioM
of fi^tire in Venus
argnethits motion
to he shut the Sun,

The MoBH
not feperatt from
theidrth-

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

G. Galil^^us, ImSjlhrne.

fcperatc from the Earth, for the rcafons that (hall be more diftinft-
]y alledged hereafter.

S A G R. I expeft that I (hail hear more admirable things that
depend upon this anEual motion of the Earrh , than werethofe
dependant upon the diurnal revolution.

r^^VuTeZ , ^ ,^ ^ , ^''^ ^^^^ ^''^ ' to the operation of

^;,/, the dmrnal motion upon the Cekftial bodies , it neither was, nor

7!rpiaL!^'\ll ^^^^^ ' "^^'^^ Uiiiverfe fecm to run precipitately

iif/ce extravagant

the contrary way ; but this annual motion intermixing with the
»;:pc»r<acc,. particular motions of all the planets , produceth very many ex-
travagancies , which have diiarmcd and non-pluft all the greatcft
Scholars in the World. But returning to our tir/t general appre-
henl.ons , 1 reply that the centre of the Celeftial converfions of
• the five plar.eis S^f«r« Jupiter, Mars, Vams and Mercury , is
the Sun i and (hall be hkewife the centre of the motion of the
Earth , ,t we do but fucceed in our attempt of placing it in Hea-
ven. And as for the Moon, this hath a cn.uiar motion about the
Earth , from which (as Ifaid before) it can by no means alienate
It leJt , but yet doth it not ceafe to go about the Sun together with
^ the Ear ch in an annual motion.

_ S I M.p, . 1 do not a$ yet very well apprehend this ftruaure , but
It may be,that with nuking a few draughts theieof , one may bet-
ter and more eafilydifcourfe^ concerning the fame.

S A L V. Tis very true .- yVa for your greater fatisfaaion and ad-
miration together , I defire you , that you would take the pains
todrawthe lame i and to fee that although you think you do not
apprehend .t , yet you very perfedly unde.ftandit ; And onely
by anlwering to my interrogations vou fliall<1rfi„ • Am,11v

fiznedfromth^P- ^^^^c papct be the nnmenie expanfion of the Univerfe in viU^^
fc^ranccs. youare to diftributc and difpolc its parts in order , according

icaf^n fliall direft you. And firft, in regard that without my i^'
ftruaion you verily believe that the Eaith is placed in this Uii^'
verfe, therefore note a point at pleafure , about which you i^^'
tend it to to be placed, and mark it wirh fome charafiers.
. S I M p. Let this mark A be the place of the Terrcftrial Globe.

S A L V. .V^ry well. I know fecondJy, that you under/land p^^
teftly that the laid Earth is not within the body of the Sun,
fo much as contiguous to it , but diftant for lome fpace {co0 the
fame, and therefore a flign to the Sun what other place y^>^ '^^^
i|ke, as remote from the Earth as youpleafe, and mark this in
manner.

M p. Here it is. done : Let the place of the Solar body

S A L V. Thefe two being conftituted , I defire that we m^J

think

ite

Dialogue lit

think of accomodating the body of Venus in fuch a manner that
its ftate and motion may agree with what fcnfibic experiments do
fliewusi and therefore recall to mind that which either by the
paft difcourfes , or your own obfervations you have learnt to be-
fal that ftar , and afterwards aflign unto it that ftate which you
think agreeth with the fame.

Simp. Suppofing thofe Phenomena expreffed by you, and
which I have likewife read in the little treat ifc of Conclufions, to

-X4-

^91

true , namely, that that ftar never recedes from the Sun beyond
f«cK a determinate fpace of 40 degrees or thereabouts , fo as that
*t never cometh either to appofition with the Sun , or 10 much as
to quadrature , or yet to the fcxtile afpeft 5 and more than that,
luppofing that it flieweth at one time almoft 40 times greater than ,„„i. th.refrc-
Jt another , namely, very great,when being retrograde, it goeth to ^j;^7:;i[r.
«ie vefpertme con jnnaion of the Sun , and very imall when with a \^

P P

motion mtt

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

tp8

Venus necejfa'
rilj f roved to move
Mhut the Sun.

Therevpluthnef
Mercury concluded
to he ahoHt the Sun^
vtthin the Orb of
Venus,

Mars neceffdrilj
includethtvithtnits
Orb the Earth^and
n/fo the Sun,

' M2t5g$itS«ppO-

fition to the SttH
(hewt to be fixty
times bigger thAft
towards the con-
juntlien.

. J jpiccr and Sa-
turn d^ likervffe en-
comtgfitheEarthy
^fdtheSnx,

G. G A L I L i^: u hir Syfleme.

motion ftiaight forwards 5 it gocth to the matutine conjunftioiij
and moreover it being true , that when it appearcth bigge it (heWS
with a corniculate figure 5 and when it appcareth little, itfeems
pcrfeftly round , rbefe appearailces,Hay,being true , I do not fee
how o«€ can choofe but affirm the laid ftar to revolve in a circle a-
boutthe Sun , for that thcfaid circle cannot in any wife be faid
toencompaffe orto contain the Earth within it , nor to be inferi-
our totheSun, that is between it and the Earth, nor yet fupe*
riour to the Sun. That circle cannot incompaffe the Earth , be-
caufe Venus would then fomctimes come to oppofition with the
Sun , It cannot be inferiour , for tjien Few/^ in both its conjunfti-
ons with the Sun would feem horned ^ nor can it be fupcriour,
tor then it would alwayes appear round, and never cornicular;
and therefore for receitof it I will draw the circle CH, about
the Sun , without encompaffing the Earth.

Salv. Having placed it is requifite that you think of

Mnwj; which, as you know, alwayes keeping about the Sun.
doth recede leffe diftance from it than Venus , therefore confia^^
with your felf, what place is moft conveniei:t to afllgn it.

S I M p. It is not to be quefiioned, but that this Planet im'f^^'
ing Venu^^ the moft commodious place for it will be a Iclfef c^^'
cle within this of Venus^ in like manner about the Sun, being
thatof itsgreateft vicinity to the Sun, an argument, an evidence
lufficently proving the vigour of its illumination, above that
Venuf . and of the other Planets, we may therefore upon thcf^
confiderations draw its Circle, marking it with the Charaftef

Salv. But Mars, Where fliall we place it ?

■,SZr oppofition with the Su^-,

Its Circle mult of neceflity encompafs the Earth ; But I fcethaf '"^
muft ncceflarily encompafs the Sun alfo, for coming to conjonfii-
on with the Sun, if it did not move over it, but were below it> '"^
would appear, horned, as Venus and the Moon i but it fliews al-
wayes round, and therefore it is neceffary, that it no lefs inclu'''
cth the Sun within its circle than the Earth. And bccaufe I f^'
member that you did fay, that when it is in oppofition with tb^
Sun It feems 60 t.mes bigger than when it is in the conjunft'^f '
mc thinks that a Circle about the Centre of the Sun,and thaff'''^-
eth in the earth, will very well agree with thefe Phanoi^"'" '
whKh I do note and mark D I, where Marsia the point V'
to the earth, and oppofitc to the Sun ; but when it is in the: poi"'
*i It is at ConjuSion with the Sun, but very far from the Earth'
«^nd becaufe the fame appearances are obfervcd in '^Hfiter aii<J
MaT' !,-^''0"gl' with muchleffer difference in 7«/i«r than «<;
WMrs^ and with yet leffcin Satmn than in Jupiter ; mc thinks 1

Dialogue 1 1

Ittderftand that we (hould very commodioufly falve all the Ph.if-
"omenaof thefe two Planets , with two Circles, in hke inannci-,
^rawn about the Sun, and this firft for jHpiter,vmxkwg K E L, and
another above that for Saturn marked F M.

S A L V. You have behaved your felf bravely hitherto. And
becaufc ( as you fee) the approach and receffion of the three Su-
Periour Planets is meafured with double the diftance between the
E»rth and Sun, this makcth greater difference m Mars Jan ,n J«-
Pter, the Circle D I, of Marf, being lelTer than the Circle EL,
«f Jxpit^r, and likewife becaufe this E L, isleffe than this Circle
F M, of Saturn, the faid difference is alfo yet leffer in Saturn than
in Jupit.r, and that punaually anfwereth the Phenomena.
It remains now that you affign a place to the Moon.

Simp. Following the fame Method (which leems to me very
conclufive) in regard we fee that the Moon comcth to conjunSion
»ndoppofitionv\^ththeSiin, it isneceffary to lay, that its cucle
f ncompaffeth the Earth, but yet doth it not follow, that it mutt
environ the Sun, for then at that time towards its con^unaion, tt
would not feem horned, but alwaycs round and full of L.ght.
Moreover it could never make, as it often doth, the Ecliple of the
Sun, by intcrpofing betwixt it and us , It is neceffary therefore
■ to aflign it a circle about the Earth, which (hould be this N P, fo
that being conftitiited in P, it will appear from the Earth A, to be
in coniunaion with theS un, and placed in N,it appeareth oppofitc
to the Sun, and in thatpofition it may fall under the Earths flia-
^ow, and be obfcured. • , i j

S A L V. Now , SmpliiiHS , what (hall we do with the hxed
fta" > Shall we fuppofe them fcattered through the immenfe abil-
fcsof the Univerle, at different diftances, from any one determi-
nate point ; or elfe placed in a fuperficies ipherically diftended a-
^put a centre of its own , fo that each of them may be equi-
^iftant from the faid centre ? i i j

S : „ , ^ would rather take a middle way ; and would affign
^Hetn an Orb defcribed about a determinate centre and comprized
Within two Ipherical fuperHcies, to wit, one very high , and con-
"ve, and the other lower, and convex betwixt wbich^^^^^^^
^onftitute the innumerable multitude A^'J^'^" ^.^1^^^^^^
y«udes,and this might be calleJthe Sphere of the Um^^,contc^n
">g within it theOrbs of the planets already by us delcriOca.

S-v. B^rwe have'all this while S..p/--^^^^^^^^^^
miindane bodies exactly, according to the order ot Cofernuzs,
and we have done it whh your hand ; and moreover to each of
them you have afficned peculiar motions of the.rown, except to
the Sun, the Earth and ftarry Sphere i and to Merc»r;r with
, you have afcrrbed the circular motion about the Sun,

Pp 2 With*-

^99

The appTOximSr
tion and recejfion cf
the three [nperiour
Planets^ importeth
double the Sms di-
fiance.

The difference §f
the apparent mag'
nitudelefe in Sa»
turn, than in Jupi-
ter, an Jupiter
f/j4»f>iMars, and
why.

The Moons Orh
invironeth the
Earth, httt not the

The proMe
fituatioH of the
fixed fiars.

ivhich ought t9
be accoHnted the
fphereof theVnt-
verfe^

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

without encompafluig the Earthy about the lame Sun you make
the three fupcriour Planets Mars, Jnpitcr, and Saturn, to move,
comprehending the Earth within their circles. The Moon in the
next place can move in no other manner than about the. Earth,
without taking in the Sun , and in all thcfe motions you agree alfo
with the fame Copcrtikm. There remains now three things to be
decided between the Sun , the Earth , and fixed ftars , namely,
mofifnandZTdt ' which fccmcth to belong to the Earth i the annual motion
Tr»liZiht 'to be wnder the Zodiack, which appeareth to pertain to the Sun j and the
di^rilfHted be- diumal motion , which feems to belong to the Starry Sphere, and
ITrlhfld^Fn- to be by that imparted to all the reft of the Univerfe , the Earth
m^vfent, excepted. And it being true that all the Oibs of the Planets, I

In 4 movcAbu mean of Mercury, Venus, Mars, Jupiter ^ ^nd Saturn, do move
2t7' tft^ ^^^"^ ^''^ Sun as their centre reft feemeth with fo much more
/W its ctrjtrebe rcafon to belong to the faid Sun , than to the Earth, inasmuch
fAtZ:r ^P*^^^^' ^"ore reafonable that the centre

Itand kill , than any other place remote from the faid centre ', to
the Earth therefore , which is conftituted in the midft of move-
able parts of the Univerfe , I mean between Venus and Mars, oU^
of which maketh its revolution in nincmoneths, and the otheri^
two years , may the motion of a year very commodioufly be af"

ttmufiof necefflt] of ncccfTary confequcuce , that likewife the diurnal motion b^'
lfim^t\o'»'T'^' '^^8^^'^ Earth j for, if the Sun ftanding ftill , the Eaff**

TdtcTtT ' ^ouid not revolve about its felf , but have oneiy the annual mo-
tion about the Sun , our year would be no other than one day an<l
one night, that is fixmonethsof day, and fix moneths of nigho
as hath already been faid. You may confider withal how commo-
dioufly the precipitate motion of 24 hours is taken away ff^>^
the Univerfe , and the fixed ftars that arc fo many Suns , are m^^^
in conformity to our Sun to enjoy a perpetual reft. You fee itiof^'
over what facility one meets with in this rough draught tore^d^^
the reafon of fo great appearances in the Celeftial bodies.

8 A G R. I very well perceive that facility , but as you from tbi^
fimplicity colled great probabilities for the truth of thatSyft^*^'
others haply could make thence contrary dedudions ', doubting^
not without reafon , why that fame being the ancient Syfteme^^*
Pythagoreans , and fo well accommodated to the rh^nom^^f ^
hath inthefuccefl:ionof fo many thoufand years had fo fe**' ^^^J
lowers , and hath been even by Ariftotle himfelf refute^?
fince that Copernicus himfelf hath had no better fortune.

S A L V. If you had at any time been affaulted, as I have been,
^^ny and many a time, with the relation of fuch kind of frivol^^^
icaions, as fcrve to make the vulgar contumacious, and difficult
DC peri waded to hearken, (1 will not fay to confent^ to this novel'

D I A L O 0 U E.

III.

301

:>( thofe who are fol-

\reonries more

?/ the impreha^i'

In J of Copernicus

Ibelievethat you wonder at the paucity
lowers of that opinion would be much diminiflicd. But fmall re-
P'd in my judgement, ought to be had of fuch thick fculs,as think 'I'^^f^^^^^^^
1^ a moft convincint^ proof to confirm, and fteadfaftly fettle them of tU

in the belief of the'^earths immobility, to fee that if this day ihey M'^*'/-
cannot Dine at Conftautpiople^ notSuf in J a ppariy that then the
Earth as being a moft grave body cannot clamber above the Sun,
^i^d then Aide headlong down again Of fuch as thefe 1 fay,
whofe number is infinite, we need not make any reckoning, nor
need we to record their foolieries , or to ftrivc to gain to our fide
as our partakers in fubnl and fublime opinions , men in whofe de-
finition the kind onely is concerned, and the difference is wanting.
Moreover, what ground do you think you could be able to gain,
all the demonft rations of the World upon brains fo ft upid ,
are not able of themfelvcs to know their down right follies ? But
"^y admiration, Sagredm , is very different from yours, you won-
der that fo few arc followers of the Fythagorean Opinion ^ and I
amazed how there could be any yet left till now that do em-
brace and follow it : Nor can I fufticiently admire the eminencie of
thofc mens wits that have received and held it to be true, and with
the fprightlintffe of their judgements offered fuch violence to their hisv^imon.
own fences, as that they have been able to prefer that which their
teafon didated to them, to that which fenfible experiments re -
prefented moft manifeftly on the contrary .That the reafons againft
Diurnal virtiginous revolution of the Earth by you already ex«
^tnined, do carry great probability with them , we have already
^^^n \ as alio that the Ptolomaicl^s^ and Anjiotelickj, with all their
Scftators did receive them for true, is indeed a very great argument
01 their cfficacic ;> but thofe experiments which apertly contradift

annual motion, are of yet fo much more manifeftly repugnant, Rcafom and Hf.
that (i f^iy if again) I cannot find any bounds for my admiration, cmrfe in Ariftat-
that reafon was able in Anfiarchm CopermcHs, to com- Ztrt.iToZ
J^it fuch a rape upon their Scnces, as in dcfpight thereof, to make
felf miftrcfs of their credulity.

S AG R. Arc we then to have ftiU more of thefe ftrong oppofiti-
^ns againft this annual motion ? y u c

^ALv. We arc, and they be fo evident and fenfible, that it a
^fnce more fublime and excellent than thofe common and vulgar,
not take part with reafon, I much fear, that 1 alio (hould have
J^en nmch more averfe to the Copcmican Sy fteem than I have been
^'"^^ the time that a clearer lamp than ordinary hath enhghtned
me.

Sagr. Now therefore Sd<uiatus , let us conie to )oyn battail
tor every word that is fpent on any thing elfc, 1 take to be caft a-
Way. ,

mamfefi fenct*

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

'Mars makes fin
hot AjfatiUHp:>n li e
Copernican Sjt-

The Phxnonic-
na o/Venus afpear
^oMtrarjf to the Sy-
fieme of Coperni-
cus.

Another diffi-
cult)! raiftdby Ve-
nus againfiQo^zi-
nicus.

V ttiMS^dccofdinjr
to Copernicus, ei-
ther iHcid tn it
felf, or elfe of *
trdnfparent fub*

Co\>zxT\\Q\xsfpealf-
eth nothing of the
frnall vdrUtion of
hignefs in Venus
and in Mars.

Jhe moon much
diftHrbeth the or-
der of the other
'Planets.

G. G A 1 1 L i?: 13 s , hk Sjflme.

S A L V. 1 am ready to ferve you. You have already leen
draw the form o( the Cofernican Syftcme ; againll: the truth of
which Mars himielf^in the firft place, makes an hot charge 3 who,in
cafe it were true, that its diftances from the earth ftouldfo much
vary, as that from the leaft diftance to the greateft, there were
twice as much difference^as from the earth to the Sun ; it would be
iieceflkry, that when it is neareft unto us, its clifcns would (he^v
more than 6o. times bigger than it fecms, when it is fartbeft from
us 5 ncverthelefs that diverfity of apparent magnitude is not to be
feen, nay in its oppofition with the Sun, when its neareft to the
Earth, it doth not fliew fo much as quadruple and quintuple in
bignels , to what it is, when towards the con;iunaion it comcth to
be occulted under the Suns rayes. Another and greater difficult)'
doth VatiM exhibit i For if revolving about the Sun, as Copermcf^
affirmeth,it were one whileabove,& another while below thelairie.
receduig and approaching to us fo much as the Diameter of the cir-
cle defcnbed would be, at fuch time as it ftould be below the Sun,
and neareft to us,its difcm would /hew little Icfs than 40 times big-
ger than when it is above the Sun, near to its other coniunaion^y^^
nevertheleire,the difference is almoftimperccptible Let us addaH'
other difficulty,that in cafe the body of yenm be of it felf darMnd
onely fhineth as the Moon, by the illumination of the Sun, vvhi^'^
ieemethmoftreaionablci it would fliew forked or horned at fuch
time as it is under the Sun , as- the Moon doth when flie is in li!^^
manner near the Sun ; an accident that is not to bedifcovercd ill
her. Whereupon Cc>^e.«i.^ affirmeth, that either /he is Jig/^t of
her felf or die that her fubftance is of fuch a nature it ca.
imbue the Solar light and tranfmit the fame through all its whole
depth, fo as to be able to appear to us alwayes fhinine • and in tW^
manner a^^.m-r^ ,he not changing figure \nVenus: b^^

ot herimall variation of Magnitude,he maketh no mention at all'
andmuch lefsof Mars than was needful ^ I believe as beine una-
ble fo well as hedefired to falve a f/;^/;.;;^.^./. fo contrary to h*^
Hypothefis,and yet being convinced by fo many other occurrence^
and reafons he maintained,and held the fame Hypothefis to be true-
^tRdcs thefe thing., to make the Planets, together with the Earth,
to move above the Sun as the Centre of their con ver/ions, and tij^
Moon onely to break that order, and to have a motion by
about the earth ^ and to make both her,the Earth, and the ^^^^^
Elementary Spbere.to move all together about the Sun in a Y^^^'
this fcemeth to pervert the order of this Syftcme which rendreth

w ""f ^''^ ^^^^^ ''^^^^ difficulties that make f

fe?v.r Ari^iarchus and Copermcus, who muft needshave ob'

vet notttl^k "^i. ^'r^ ^" ^^^^^ ^« ve thep, hav^

yet notwuhftandmg by other admirable occurrences been induced

fe
n<

ai
th

ui
V
in

tb
fo

o
t

i
1

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

I ALOGUE.

III.

Confide fo much in that which reafon diftated to them, as that
they have confidently affirmed that the ftrufture of the Univerfe
could have no other figure than that which they defigned to them- ^
felves.There are alfo feveral other very ferious and curious doubts,
not foeafie to be refolvedby the middle fort of wits, but yet pe-
netrated and declared by Coperninus^ which we fiiall defer till by
and by, after we have anfwered to other ob)etiions that feem to
Riakeagainft this opinion. Now coming to the declarations and
^Jyt ^nfwers to thofe three before named grand ObjeSions, I fay, tha^

the two firft not onely contradjft not the Copcrnican Syfteme, but ^nfwemotbe
greatly and ablblutely favour it *, For both Mars and Vznu^ fcems three firft okjeai-
jncqua] to themrLlves,according to the proportions afligned ^ and '^^^^f^^^^^^
y^nns under the Sun feemeth horned, and gocth changing figures ^ ^
in it felf exaaiy like the Moon.

S A G R. But how came this to be concealed from CopernicHS^
and revealed to you >

S A L V. Thefe things cannot be comprehended, -fave onely by
^he fenfe of feeing, the which by nature was not granted to man
as that it was able to attain to the difcovery of fuch dif-
ferences j nay even the very infi:rument of fight is an impediment
to it felf : But fince that it hath pleafed God in our age to vouch-
fefeto humane ingenuity, fo admirable an invention of pcrfefling
our fight, by multiplying it four, fix, ten, twenty, thirty, and four-
ty times, infinite ob)e£l:s, that either by reafon of their diftance, or
for their extream fmallnefle were invifible unto us, have by help
^f the Telefcope been rendered vifiblc.

Sagr. ButVint^s^LadMars arc none of the objefts invifible
their diftance or fmallnefle, yea, we do difcern them with our
bare natural fight ; why then do we not diftinguifli the difFerencci
ot their magnitudes and figures?

S A L V. In this, the impediment of our very eye it felf hath a Tkereafia whence
great fliarc, as but even now 1 hinted, by which the refplendent and l^^t^'lTMrJ^
^cttiote objefts are not reprcfented to us fimple and pure ^ but gives appear to v*rj
J^m us fringed with ftrange and adventitious rayes, fo long and "^J^^^^^^^^^^^^
denfe, that their naked body flieweth to us agrandixed ten, twen- '^'''^

5 an hundred, yea a thoufand times more than it would appear, if
^ ^^^^pillitious rayes were taken away.

S A j^^^ J remember that I have read fomething on this
^ubjea, 1 tnow not whether in the Solar Letters, or in the Sag^
^^^^oTz of our common Friend, but it would be very good, afwell
^^ecalling it into my memoty, as for the information of Simpli^
who it may be never faw thofe writings, that you would de-
clare unto us more diftindly hovv this bufinefle ftands, the know-
Jcdge whereof l think to be very necelfary for the aflifting of us to
^nderftand that of which we now fpeak.

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

3^4

The operAtloffs of
the Tefefcope ac-
counted fallacies
the Peripacecicks.

G. G

A L 1 L ^ U S

his Sjfii

kmc.

shining objeEis
feem environed
with adventitious
TMjes,

The reafon why
luminous bodies ap'
fear enUrged
mmch the more , bj
how much they are
lefer.

Superficial fi-
gures cncreafiing
proportion double to
I heir lines.

S i m p. I niuft confeffc that all that which Salviatus hath fpo-
ken is new unto me, for truth is, I never liave had the curiofity to
read thofe Books, nor have I hitherto given any gicac credit to
the Telefcope newly introduced j rather treading in the fteps of o-
ther Pcri;?^/efir^ Philofophers my companions, I have thought
thofe things to be fallacies and delufions of the Chryftals, which
others have fo much admired for flupendious operations :
therefore if I have hitherto been in an errour, I (hall be glad to be
freed from it, and allured by thefe novelties already heard from
youj I fliall the more attentively hearken to the reft.

S A L V. The confidence that thefe men have in their oWn ap-
prehcnfiveneffe, is no lefs unreafonable than the fmall efteem they
have of the judgment of others : yet its much that they fliould e-
Iteem themielves able to judge better of fuch an inftrument, with-
out ever having made trial of it, than thofe who have made, and
daily do make a thoufand experiments of the fame : But I pr^^Y
you, let us leave this kind of pertinacious men, whom we can-
not fo much a? tax without doing them too great honour. And re-
turning to our purpofe, I fay, that refplendent objeas, whether
It IS that their light doth refraft on the humidity that is'upo/i the
pupils, or that it doth refleft on the edges of the eye-browes,
fufing its reflex raycs upon the faid pupils, or whether it is for io^^
other reafon, they do appear to our eye, as if they were environ'^
with new rayes, and therefore much bigger than their bodi^^
would reprcfent themfelves tons, were they divefted of thofe i^'
radiations. And this aggrandizement is made with a greater afli
greater proportion, by how much thofe lucid obiefls are leffer anJ
Icffer i in the fame manner for all the world, as if we ftould fuf
L jj^^^ augmentation of fliining locks were four inched'
which addition being made about a circle that hath four inches ^J^-
ameter would increafe its appearance to nine times its former big-
neffe : but .

Sim P. I believe you would have faid three times ^ for adding
four inches to this fide, and four inches to that fide of the dia^^^
ter of a circle, which is likcwife four inches, its quantity is thefC^
by tripled, and not made nine times biga^r.

Sai. V. A little more Geometry woufd do well Simfl^^^^^'
True it is, that the diameter is tripled, but the fuperficies, which
that of which we fpeak, increafeth nine times : for you muft k^^^'
Simplicins, that the fuperficies of circles are to one anoth^r^
the Iquaresof their diameters i and a circle that hath fouf '^^^^^^^
dumeter is to another that hath twelve, as the fquare of four t|[
VH^are of twelve that is, as 1 6. is to 1 44. and therefore it M

ni/nT.'"''? "'''^ ^^"^^^> """^ ^^'^^ ' ^^''^ way of advertite-
mcnt to Simpliciu^^ And proceeding forwards, if we /hould add

^ the

I A L O (3 U E

Hi.

hey

faid irradiation of four inches to a circle that hath but tWoin^
^*^es of diameter onely, the diameter of the irradiation or Gar-
W would be ten inches, and the fuperficial content of the circle
^<iuldbe to the area of the naked body, as loo. to 4. for thofe
^rethefquaresof 10. andof 2. the agrandizemcnt would there-
fore be 25. times fo much and laftly, the four inches of hair or
f'*it^ge, added to a fmall circle of an inch in diameterj the fame
Would be increafed Si. times j and fo continually the augmenta-
tions are made with a proportion greater and greater, according
as the real objefts that increafe, are Iclfer and lelTer.
S A G R. Xhe doubt which puzzled Siift^liciHS never troubled
but certain other things indeed there are, of which I defirc
a more diftinft underftanding?, and in particular, I would know up-
on what ground you affirm that the faid agrandizement is alwayes
^qualinallvifibleobjcfis.

Salv. I have already declared the fame in part, when I faid,
^hat onely lucid objefts fo incrcafed, and not the obfcure \ now I
adde what remaines, that of the refplcndent ob^eds thofe that are
of a more bright light, make the refleaion greater and more re-
•plcndcnt upon our pupil ; whereupon they fecm to augment
^ch more than the leffe lucid : and that I may no more inlarge
my felf upon this particular, come we to that which the true Mi-
ftris of Aiironomy^ Experience, teacheth us. Let us this evening,
^hcn the air is very obfcure, obferve the ftar of Jupiter *, we
fcall fee it very glittering, and very great h let us afterwards look
through a tube, or clfe through a fmall crunk, which clutching the
•^and clofe^ and accofting it to the eye, we lean between the palm
of the hands and the fingers, or elfe by an hole made with a fmall
IJeedlein a paper*, and we (hall fee the faid ftar diverted of its
oeams, but fo fmall, that we (hall judge it leffe, even than a fixti-
part ofits great glittering light feen with the eye at liberty:
may afterwards behold the Dog-far s beautiful and bigger than
^^^yof the other fixed ftars, which feemeth to the bare eye no
S^eat matter Icffe than jfwfifcr-, but taking ftom it, as before, the
'''^^iation, its Difcns will (hew fo little, that it will not be
*^^§ht the twentieth part of that of J^ptcr, nay, he that hath not
j^^^y good eyes will very hardly difcern it i from whence it may
rationally inferred, that the faid ftar, as having a much more
^^^ly light than Jupiur, maketh its irradiation greater than Jupi^
^^^ doth his. In the next place, as to the irradiation ot the Sun
^nd Moon, it is as nothing, by means of their magnitude, which
poflcfTethof itfclfalone fogreatafpaceinour eye, that it lea-
veth no place for the adventitious rayes \ fo that their faces feem
^lole dipt, and terminate. We may affure our fclves of the fame
^"^uih by another experiment which I have often made triallof?

object tht mere
vigor oMt they ar»
in lighty the mere
thejd§ feem 1 9 in*
creafe.

%An eMpe exfe'
riment that jhev^^
etb theincreafe in
thefiars^ hy means
of the adventitioHS
rays^

Jupiter augments
lejfe than the Vo^-
ftar.

The Sun and
Moon ivcretife
tte.

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B.9,163

3o6

O. G

ALIL^US,

his Syfii

It is fecK hj W4-
wfefi experience^
that the wore
fflendid bodies do
mnch more irradi-
ate than the lejfe
lucid*

The Tclefcope
uthebeftmtAnt tt
take dtvay the ir*
radiations of the
Stars,

Another [econd
reafoHofthefmali
apparent increafe
of Venus.

Copernicus per^
fwaded by reafozs
contrary to [enftble
experiments.

wemayaffure our felves, I fay, that bodies. iliiiing with moft liv^'
ly light do irradiate, or beam forth rayes ijiore by far than thofc
that are of a more languifhing light. I have many times fecn ']^'
piter and Venus together twenty, or thirty degrees diftant from
Sun, and the air being very daA, Fe/i/*^ appeared eight or ten
times bigger than Jupiter, beiogboth beheld by the eye at li^^^'
ty i but being beheld aftcrvy^ards .with the Telefcope, the Dif^^^
of Jupiter difcovered it felf tobe four or more times greater thafl
that of Venus ^ but the vivacity of the fplendour of Vemts was in'
comparably bigger: than the languifliing light of Jupiter h ^hicb
ws^s only becaufe of Jupiters being far from the Sun, and f^om us5
and Venus neer to us, and to the Sun. Thefe things premifed? ^
will not be difficult to compreheiid, how Mars,when it is in oppo'
/ition to the Sun, arid therefore rieerer to the Earth by feven time^?
and more, than it is towards the conjunftion, cometh to appe^^
fcarce fout or five times bigger in that ftate. than in this, when a^i^
(hould appear more than fifty times fo much , of which the on'y
irradiatioR Js the caufe j for if we diveft it of the adventiti^^
rayes, we fliall find it exaftly augmented with the due proportion*
but to takeaway the capillitious border^ the Telefcope is the b^*^
and only means, which inlarging its Difcus nine hundred ^ ^
thoufand times, makes it to be feen naked and terminate, as tbi*|
of the Moon, and different from it felf in the two pofitions?
cording to its due proportions to an hair. Again, as to V^^^^^
that inits vefpertine conjunftion, when it is below the Sun, ovi^^
to fliew almoft fourty times bigger than in the other matutine coP*
jundion, and yet doth not appear fo much as doubled 3 it happef^
eth, befides the effeft of the irradiation, that it is horned !» and i^^
crefcents, befides that they are fliarp, they do receive the Suns lig'^^
obliquely, and therefore emit but a faint fplendour ^ fo that
being little and weak, its irradiation becometh the lefTe aUipjj
and vivacious,than when it appeareth to us with its Hemifph^^^
fliining; but now the Telefcope manifeftly fliews its hornes
have been as terminate and diftinft as thofe of the Moon ,
appear, as it were, with a great circle, and in a proportion tM^
well neer fourty times greater than its fame Difcus, at fu^^ ti^^
as it is fuperiour to the Sun in its ultimate matutine apparition-

Sag k. Oh, Nicholas Copernicus, how great would hav^ ^^^^
thy joy to have feen this part of thy Syftcme, confirmed ^'^^^
raanifeft experiments !

S A L V. Tistrue. But how much leffe the fame of hi« f^bli^^^
amongfl: the intelligent ? when as it is feen, as I alfo faid befof^
that he did conftantly continue to affirm (being pcrfwaded therct
by rcafon) that which fenfible experiments feemed to contradi^ '
for lcannotccafeto wonder that he fliould conftantly
faymg, that revolvcth about the Sun, and is more than

D I A L O G U E I I I-

times farther from as at one time,thah at another , and alfo feem^^

Q30

cthtobe alwaycs of an equal bignefs, although it ought to Oievv
ft>rcy times bigger when neareft to us, than when fartheft off.
Sagr. Qwi'm Jpipiter, Saturn and Mercury, I believe that
differences of their apparent magnitudes^fhould fecni punftu-
illy to anlwer to their different diftances.

S A L V. In the two Superiour ones, I have made precife ob-
fervations yearly for this twenty two years laft pail : In Mercury
there can be no obiervation of moment made, by reafon it fuf-
fers not it felf to be feen , fave oncly in its greateft digrfficons
from the Sun, in which its diftances from the earth are infentlbly
^nequal^ and thofe differences confequently not to be obferved ^
p alio its mutations of figures which muft abfolutely happen in
as in Ven^s, And if we do fee it, it muft of neccflity appear
in form of a Semicircle, as Te^wx likewife doth in her greateft
^effions ; butitsaz/c/zj-isfo very fmall, and its fplendor fo
^^^■y great, by reafon of its vicinity to the Sun, that the virtue
of theTelefcope doth not fufficc to clip its treflbs or adventitious
^^ycs, fo as to make them appear ftavcd round about. It re-
"^^ins,that we remove that which teemed a great inconvenience
in the motion of the Earth, namely that all the Planets moving
5>bout the Sun, it alone, not folitary as the reft, but in company
With the Moon, and the whole Elementary Sphear,fliould move
tound about the Sun in a year*, and that the faid Moon withal
Ihould move every moneth about the earth. Here it is neceflary
Qivce again to exclaim and extol the admirable perfpicacity of Co-
t^rnicus^ and withal to condole his misfortune, in that he is not
now alive in our dayes , when for removing of the feeming ab-
furdity of the Earth and Moons motion in confort we fte Jtipi-
as if it were another Earth, not in confort with the Moon,
out accompanied by four Moons to rovolve about the Sun in 12.
years together, with what ever things the Orbs of the four Mcdi-
^*an Stars can contain within them. ^

S A L V. Why do you call the four jovial Planets, Moons ,
^ S A G R. Such they would feem to be to one that ftanding in
J^'f'ter ftould behold them for they are of themfelves dark,and
^^^^ive their llaht from the Sun, which is manifeft from their bc-^
^^g e^lipfed, when they enter into the cone of Jnftters fliadow :

J L , ' . . ./'I ^1 i^/^lr t^r» warns tru

Mercnry admit'
teth not of cluf

The dificu/c
removed that artfe
ficm the Earths
ntsvin^ alfont the
Snn^Hot foUtariljy
hut tn confort with
the Moon,

The Mediccan
Stars areas dp were

four \Aootts ahoHt
>itei.

Jupit

,n the uppir parts of their circles ; but in the pa,
^«r, that is between and the Sun, they would trom Ju-

hter\K obfervcd to be horned ; and in a word they would, to

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

joS G. G A L I L ^ u s, bis Syjiemc.

the obfervators ftanding in Jupiter^ make the Iclf fame changes
of Figure^, that to us upon the Earth, the Moon doth make. Yott
fee now how thefe three things, which at iirft fecmed dilTonant,
do admirably accord with the Coperrncan Syfteme. Here alfo by
the way may Stmpltcius fee, with what probability one may con-
clude, that the Sun and not the Earth, is in the Centre of the
Planetary conwQr{ions. And fmce the Earth is now placed a-
mongft mundane Bodies,that undoubtedly move about the S^^^i
to wit, above Mercnry and Venp^^ and below ^aturn^ Jufitef,
and Mars fliall it not be in like manner probable, and perhaps
ncceffary to grant, that it alfo moveth round ?

'S i i4fv - Thefe accidents are fo notable and confpicuous, that
it is not poflible, but that Ptolomy and oihers his Seciators,fliouW
have had knowledge of them, and having fojit is like wife necei*
fary, that they have found a way to render reafons of fuch, an^*
fo fenfibleappearaiices that were fufficient, and alfo congruoU^
and probable, feeing that they have for fo long a time beent^'
ceived by fuch numbers of learned men. ,
The Prhcipal S A L V. You atgue Very well j but you.know that the princip^
fcepe of rem- ^ ^£ Afironomers \s to render only reafon for the appearance^

mersi ts to give a \ , i , i i - C tht

reafon of appear- in the Cxleftial Bodies, and to them, and to the motions or i'^*'
Stars,ro accomodate fuch-ftrufiures and compofitions of Clt^^^j
that the motions following thofe calculations, anfv^er to tbef^
appearances, little fcrupling to admit of fome exorbitances, tb^
indeed upon other accounts they would much ftick at. And C^'
Jfo^TJ^irolZr pernio Hs himfelf writes, that he had in his firft ftudies reftored tbj
upon the fuppofti' Scicuce of -^J^rowfj^)' upon the Very fuppolitions of ftolo^y->^'^
Ptolomy. in fuch manner correded the motions of the Planets, thatth^
computations did very exaftly agree with the ^h^nomena^ aii^
the Vh^nomena with the fupputations, in cafe that he took ^
Planets feverally one by one. • But he addeth, that in going ^'
bout to put together all the ftruftures of the particular Fabric^^
there reiulted thence a Monftcr and ChimarayCo mpofed o{f^^^
bers moft difproportionate to one another, and altogether i^^^^^^
patiblc^ So that although it fatisfied an Aftronomer meerly ^
riihmctical^ yet did it not afford fatisfaftion or content to ^
Ajlronomer PhylofophicaL And becaufe he very
ftood, that if one might falve the Gaelcflial appearances with
affumptions in nature, it might with much more eafe be do^^ J|
true fuppofitions, he fet himfelf diligently to fearch wbetb^^
ny amongft the antient men of fame, had afcribed to tbe y ,
any other ftrufture, than that commonly received by F^^^^^^ ^
and finding that fome Pythagoreatts had in particular ^^J^^^l,
the Diurnal converfion to the Earth, and others the annual
tion alfo, he began to compare the appearances, and patticu ^.^^

what movedCor
pernicus to efik'
il'jhhisSjPwe.

Dialogue.

309

ties of the Planets motions, with thefe two new fuppoiitious, all
which things jumpt exaaiy with his piirpofejand ledng the whole
c^kfpond, with adinirable facility to its parts, i he imbraced this
i^^ Syfteme, and it took up his reft. .
^ 'S I M p. But what great cxorbit^ncies are there in the, Ff^w-
»ft*tci^ ^yfrerne^for which there are not greatep tobe found in this
^ Gopernu^^l - ' ^ ^ . ^T^^

"''S'A L-v. In the Ptolomaick Hypothefis thci^e ate dtfeales^anq in
the Copernican their cures. And firft will not all the Seds of
Phylofophers, account it a great inconvenience, that a body na-
turally moveable in circumgyratioo^fliould move irregularly upon
its own Centre, and regularly upon another point ? And yet
there are luch deformed motions as thefe in the Ttolom^an Hypo-
^J^efis, but in the Copernican all move evenly about their own
Centres. In the Ptolomaick-> it is necelfary to affign to the C»-
'^ftial bodies, contrary motions, and to make them all to move,
*^^om Eaft to Weft, and at the fame time, from Weft to Eaft
^^t in the Copernican , all the Caeleftial revolutions^ are towards
one onely way, from Weft to Eaft. But what fliall we fay of
the apparent motion of the Planets,fo irregular, that they not on-
ly eo one while fwift, and another while Qow , but fometimes
Wholly feace to move and then after a long time return backa -
gain?To falve which appearances Ptolomie introduceth very great
EpicicUs, accommodating them one by one to each Planet, with
feme rules of incongruous motions, which are all with one fin-
gle motion of the Earth taken away. And would not you, Sim-
flicitps^ call it a great abfurditie, if in the Ptolomaick^ Hypothe-
fi^^:> in which the particular Planets, have their peculiar Orbs af-
figned them one above another, one muft be frequently forced
to fay, that Mars, conftituted above the Sphaerc of the Sun,doth
fo dcfcend, that breaking the Solar Orb, it goeth under it, and
approacheth nearer to the Earth , than to the Body ot the Sun ,
^ndby and by immeafurably afcendeth above the fame ? And
• yet this, andotherexorbitancicsare remedied by the iole and
fingle annual motion of the Earth. t r a -

S A G R. I would gladly be be ttter informed how theie stations,
retrograde and direft motions, which did ever feem to me
gi-eat improbalities, do accord in this Copernic^u Sylteme.

Salv. You (hall Tee them fo to accord, 5^^r^^^^
this onely coniedure ought to be fufficient to make one that
^^'notm.re than pertinacious or ftupid , yield, affent to all the
^^ft o£ this DoSrine I tell you therefore , that nothing being
altered the motion of SatnrH , which is 30 years , in that
of JnpiUr, which is 1 2 , in that of Mars, which is 2 , in that of
yenm, which is 9 moneths v in thatof Merw;' , which is 80.

daycs.

IncoKvenitMcies
that are in the S/-
fieme ^>/Ptolomy^

Its Agrmjir'
gument in fdVfiur
of CopzxnicuSyt hat
he obviates the fi^
tions&rttrogr^dA-
tiomof the motioni
of the TUnetf.

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

510 G. Galil^us^ hisSyjitme.

daycs, or thereabouts , the fole annual motion of the Earth bc-
7he Cote annual ^^^^^ ^^^'"^ ^^^^ , caufcth the apparent inequalities in all
motiol \Y*"'The the five ftars before named. And for a facile and full under-
Earth caufeth ftandiug of the whole , I will defcribe this figure of it. There-
^ZZZlZlifit fo^^ fuppofe the Sun to be placed in the centre O, about which
"Planets. wc Will draw the Orb defcribed by the Earth , with the an-

nual motion B G M , and let the circle defcribed , ^r. by
Jupiter about the Sun in 1 2. years > be this b g m , and in the

llf::;^ f'''^^^^r%'TV*"^f r ^"^^^^'^ Y^S. Again, in th^
the three f^pnhJr annual Orb ot the Earth let us take certain equal arches, BC,

r«r.irtr !^ ^ H I K. K L, LM , and in theSph^^f

ts^ncf the Earth.' 7^P^^^^ "^^^e certam other arches, palTed in the (^'^^

times in which the Earth pafTeth hers, which let be b c , ^

DE,EF,FG,GH,Hl5lK,KL, LM, which ftall ^^^^

proportionally lelTe than thefe marked in the Earths O^b , lik^
*s the motion of Jupiter under the Zodiack is flower than the
f nnual. Suppofing now , that when the Earth is in B, Jupiter is
in B , It (hall appear to us in the Zodiack to be in P defcribii^g

the

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

Dialogue. HI.

^l^e right line B bP. Next fuppofe the Earth to be moved from
^ to C 5 and Jupiter from b to c 5 in the fame time j Inpiter
appear to have paffed in the ZodiacktoIX, and to have
"^ved ftraight forwards , according to the order of the fignes
In the next pla<:e , the Earth pafling to D , and Inpiter
^ it fhall befeenin the Zodiack in R , and from E \; lupi-
being come to e h will appear in the Zodiack in S , having
this while moved right forwards. But the Earth afterwards
beginning to interpofe more directly between Jjif/^^/* and the
^i^) fhe being come to F, and lupiterto f i he will appear in
to have already begiin to return apparently back again un-
the Zodiack , and in that time that the Eaith lliall £ive paf-
tfacarchE F, Inpiter (hzW have entertained himfelf between
points ST 5 and fliall have appeared to us almoft motion-
'^ffe and ftationary. iFhe Earth being aft-erwards come to G,
*Qd Inpiter to G , in oppofition ; to the Sun , it fliali be vifible in
Zodiack at V , and much returned backwards by all the arch
the Zodiack T V , howbeit that all the way purfuing its even
^^nrfc it hath really gone forwards not onely in its own circle,
^Wt in the Zodiack alfo in refpeS to the centre of the faid Zodi-
^ck , and to the Sun placed in the fame. The Earth and Inpiter
again continuing their motions ^ when the Earth is come to H,
^nd Inpiter to n , it fliall feem very much gone backward in the
Zodiack by all the arch V X. The Earth being come to!-, and
^Hpiter to i 5k fliall be apparently moved in the Zodiack by the lit-
tlefpaceXY, and there it will feem ft: tionary. When atter-
wards the Earth fliall be come to K, and Inpiter to k 5 in the
-Zodiack he fliall have paffed the ^rch Y N in a dircft motion h
3nd the Earth purfuing its courfe to L , fliall fee Inpiter in L , in
the point Z. And laflly Inpiter in m fliall be feen from the Earth
^> to have pafled to A 5 with a motion ftill right forwards , and
*t« whole apparent retrogadation in the Zodiack fliall anfwer to
^'^^arch SY, m^dc by Inpiter ^ whilflthat he in his own circle
P^ffeth the arch e i , and the Earth in hers the arch E I. And
which hath been faid, is intended of Saturn and of Mars
h and in Satnrtt thofe rctrogradations are fomewhat more
y'^qUentthan in Jupiter, by reafon that its motion is a little
f^"^^' than that of Jupiter , fo that the Earth ovcrtaketh it
*t ui a (horter fpace of time h in Mars again they are more
for that its motion is more fwift than that of Jupiter.
^^^^ipon the Earth confumcth more time in recovering it.Next
"^yo Fen^ and Merc;^r;^,whofe Circles are comprehended by that
Earth, their ftations and regreflions appear to be occafi-
^ned, not by their motions that really are fuch, but by the anual
"lotion of the faid Earth, as Copernicm cxellently 'demonftratcth,

311

to-

Retrogradstitns
more frccjuent if*
Saturn, /ejfein]\i-
picfr, andyetlejft
««Mars, atidwh/.

The RetrtgrAdd"

tionef Venus and
Mercury dfrnoK-
firated hy Apollo-
nius and Coperni-
cus»

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

912

The anntiil nio-
tioM of the Earth
mojh apt to render
Urea fan of the ex -
orhitances of the
five Planets.

The Sun it felf
tefitfieth the anntt'
al motion to belong
to the Earth,

G. G

A L I L ^US

his Sjfti

erne.

The LjncaAH
9^cademick^ the
firjf difcoverer »f
the Solar f pots, and
Mil the other cele-
ftiai novelties.

The hijtory of
the froceedings of
the ^CAdemian
for a long time a-
toMt the olffervati-
on of the SoUr
fpots,

* Duu^iviro.

together with Affollonius Pergam in lib. 5, of his Revolutions^

You lee,Gentlemen, With what facility and fimplicity the annu-
al motion, were it appertaining to the Earth, is accommodated
to render a reafon of the apparent exorbitances, that are obfervcd
in the motions of the five Planets, Saturn^ Jupiter^ Mars , Ve*
«»5and Mercury i taking them all away, and reducing them to
equal and regular motions. And of this admirable effeftj Ni'
cholas CopjrnicH'Sy hath been the firft that hath made the reafon
plain unto us. But of another effeft, no lefTe admirable than
this, and that with a knot , perhaps more difficult to unknitj
bindeth the wit of man, to admit this annual converfion, and to
leave it to our Terreftrial Globe h a new and unthought of con-
jefturc arifeth from the Sun it felf, which flicweth that it is unwil'
ling to be Angular in fliifting, of this attellation of fo eminent a
conclufion, rather as a teftimony beyond all exception? it hath
defired to be heard apart. Hearken then to this great andncv^
wonder.

The firft difcoverer and obferver of the Solar fpots, asalfo^>f
all the other Coeleftial novelties,was our Academick^Lincaf^h^^
he difcovered them anno 1610. being at that time Reader

of the

Mathematickjy in the Collcdge of f and there, and in

wice, he difcourfcd thereof with feveral perfons , of which fol^^
are yet living : And the year followingjhe fliewed them in K.^'
to many great pcrfonages, as he relates in the firft of his Lettci'S
to Marcus Velferus , ShcrifFe of Augnfta. He was the
fiift that againft the opinions of the too timorous and too Jealous
affertors of the Heavens inalterability, affirmed thofe fpots to
matters, thatinfliort times were produced and diflblved : fof^^
to place, they were contiguous to the body of the Sun , and f^'
volvedabout the {ame 3 orelfe being carried about by thcftj^
Solar body, which revolvcth in it felfe about its own Centre,
the fpacc almoft of a moneth, do finifli their courfc in that tiin^ 1
which motion he judged at firft to have been made by the Sun
bout an Axis erefted upon the plane of the Ecliptick ^ in regard
that the arches defcribed by the faid fpots upon the Difcft^^ of the
Sun appear unto our eye right lines, and parallels to the p'^'^^.^ij
the Ecliptick : which therefore come to be altered, in part,
fome accidental, wandring, and irregular motions, to which ^'^^X
are fubjeft, and whereby tumult uarily, and without any ^^^^^
^hey fucceffively change fituations amongft therafclves? one
p^hile crouding clofe together, another while difTevcring,
lome dividing themfelves into many and very much changing
gures, wluch, for the moft part, are very unufual. And albeit
thole foinconftant mutations did foraewhat alter the primary P^*

riodick

uc J

Di ALOGUE* I 11. ^I^

riodick courfe of thcfaid fpots, yet did they not alter the opini-
on of our friend, fo as to make him beheve, that they were any
^ffential and fixed caufe of thofc deviations, but he continued to
' '^old, that all the apparent alterations derived themlelves from
^hofe accidental mutations : in like manner, juft as it would hap-
pen to one that fhould from far diftant Regions obferve the mo-
tion of our Clouds , which would be difcovered to move with St
moft fvvift, great, and conftant motion, carried round by the di-
^^^nl Vertigo o( the Earth (if haply that motion belong to the
fame) in twenty four hours, by circles parallel to the EquiiiodH-
al, but yet altered, in part, by the accidental motions caufed by
the winds, which drive them, at all adventures, towards diiFerent
Starters of the World. While this was in agitation, it came to
pafs that Vclferm fent him two Letters, written by a certain per- ^ ^^.^ ^^^^^^^
^^^iWixd^i the feigned name of * Afelles-, upon the fubjeft of tmcnamcis chn-
^'^^ie Spots , requefting him, with importunity, to declare his {'f^^^^^'^'l^^
thoughts freely upon thole Letters, and withall to let him know BooriiJre mean'c
^hat his opinion was touching the effence of thofc fpotsj which his »s intituled, jsptl-
^equeft he fatisfied in 3 Letters, (hewing firft of all howvain the rfl'^'*^*"'^
conjcftures of ApeUes werej & dircovering,fecondly,his own opi-
^ions^ withal foretelling tohim,that Afelles would undoubtedly
l>e better advifed in time, and turn to his opinioujas it afterwards
Came to pafs. And becaufe that our Academian (as it was alfo
the judgment of many others that were intelligent in Natures fe-
^^'^ets) thought he had in thofe three Letters invcftigated and dc-
^onftrated, if not all that could be defired, or required by hu*
^*^anc curiofity ^ at leaft all that could be attained by humane
^ifon in fuch a matter, he, for fome time (being buficd in other
ttudies) intermitted his continual obfervations, and onely in com-
placency to fome friend, joyned with him, in making now and
^f^en an abrupt obfervation : till that he, and after fome years,

being then at my * Country-feat, met with one of thefolita- "^'^ ^iiu

VI Solar fpots very big, and thick, invited withal by a clear and
Conftant ferenity of the Heavens, he, at my requeft, made obfer-
vations of tlie whole progreffe of the (aid fpot, carefully marking
"P^t^ a flieet of paper the places that it was in every day at the
time of the Suns coming into the Meridian and we having found
that Its courfe was not in a right line, but fomewhat incurvated,
came to rcfolve, at laft, to make other obfervations front time
^^^*»tne^ to which undertaking we were ftrongly induced by a
^^^^ accidentally came into the minde of my Gucft,
Which he imparted to me in thefe or the like words.

In my opinion, Fhilif, there is a way opened to a bufmefs of
very great confcquence. For if the Axis about which the SUn
^tirneth be not ereft perpendicularly to the plane of the Eclif-

R r tick,

514 G. Galilaus^ his Sjfleme.

camepZj^^^^^^ ^^^^^ ^^^^ incUncd upon the fame, as ics aooked courfe, hnt ^
to the minde of vcii iiQW obferved, Hiakes me belie ve, wc fliall be able ta make
Ly'nc^'™' ^"^.^^ con jedures of the ftates of the Sun and Earth, neither &>
ing the great con- folid or fo rational have been hitherto deduced from any other ac^- »

cidentwhatfoever. I being awakx^ned at fo great a promife, im^
tion of the. Solar portun d Mm to make a free dilcovery of his conceit unto me.
ffots. And he continued his difcourfe to this purpofe. If the Earths

taihmtoioHcr. motion Were alotig the Ecliptique about the Sun i u\A the Suo
vidin themoiicns were conftxtutcd in the centre of thefaid Ecliptick, and therein
icTbjthS'i revolved in its felf, not about the Axis of the laid Ecliptique
dtmicK , (which would be the Axis of the Earths annual motioa) but up-

tnlTl^ut''"' on one inclined, it muft needs follow, that ftrange changes wiH
reprelent themlelves to us m the apparent motions of the Solaf
fpots, although the faid Axis of the Sun ihould be fuppofcd t"
perfift perpetually and immutabjy in the fame inclination, anJi"
one and the fame direftion towards the felf fame point of th«
Univerfe. Therefore the Terreftrial Globe in the annual motio"
movmg round it, it will iirft foiiow, that to us, carried about b-y
the fame , the courfts of the fpors fliall fometimcs lVem to
made in right lines, but this only twice a year, and at all ati"
times lliall appear to be made cy arches infenfibly incurvatc<l-
Secondly, the curvity of thofe arches for one half of the ye*^'
will fliew inclined the contrary way to what they will appeal'*
the other half i that is, for fix moneths the convexity of the**'
ches {haU be towards the upper part of tile Solar DiicHS, and fo'
the other fix moneths towards the inferiour. Thirdly the fpots be-
gmmng to appear,and (if 1 may fo ipeak) to rife to our eye frotf
the left fide o the Solar l^./c^, and going to hide thcmfelv^'
^nd to fet in the right fide, the Oriental termes, that is of i^'^
firft appearings for fix moneths, fliall be lower than the oPp"^'^
termes of their occultations ; and for other fix moneths it ft*''
happen cpntrarily, to wit, that the faid fpots rifing from mote
levated points, and from them defccnding, they fliall, in t^eif
.courfes, go and hide themlelves in lower points i and oiiely
tWQ 4i>yes in all the year fliall thofe termes of rifings and
tings be equilibrated after which freely beginning by fmall de-
crees the inclination of the courfes of the fpots, and day by i%
growing bigger, in three moneths, it fliall arrive at its gr^^'^
^b)iquity,and from thence beginning to diminifli, in fuch aiK'^''^'^
.time it fliall reduce it felf to the other jEquilihrium. It ft*" '"f
sen, for a fourth wonder, that the courfe of the greateft obl'*
quity fliall be the fame with the courfe made by the ng^<^ ''''^'
^nd in the day of the Libration the arch of the courfe fliall feej
na «*.K ^"""^ incurvated. Again, in the other times, accof^*'
-mgasthe pendency fliall fucceffively diminifl,, and make its ap-
proach

Dl ALOGUE.

lit.

)ft of the archei

The firfl Ac-
cident to he ohfer"
vrd in the motion
of the Solar fpots ;

pioach towards the R^nilibritint^ the incurvatio

the courfcs on the contrary ftiall, by degrees, incrcafe.
Sagr. Iconfeffe, SahiatHS^ that ro interrupt you in youi"
Difcourfe is ill manners, but I efteem it no Icffe rudenefs to per-
5^it youtorun on any farther in words, whilft they are, as the
laying is, cafl: into the air : for, to fpeak freely, I know not how
^0 form any diftinft conceit of fo much as one of thcfe conclufi-
^^^s, that you have pronounced j but becaufe, as I thus genetal-
V ^ndconfulcdly apprehend them, they hold forth things of ad-
"^ii'able conlcquence, I would gladly, fome way or other, be
^^ade to under ftand the fame.

Lv. The fame that befalls you, befell me alfo, whilft my
^ueft tranfported me with bare words ^ who afterwards aflifted
^^iy capacity, by defcribing the bufineffe upon a material Inftru-
J^ent, which was no other than a fimple Sphere, making ufe of
^^meof its circles, but to a different purpofe from that, to which

are commonly applied. Now I will fupply the defeft of confe^uentlj
thq Sphere, by drawing the fame upon a piece of paper, as need alltht tefiexpUt-
fhall require. And to reprelent the firft accident by mc propoun-
^ed, which \vas, that the courfes or journeys of the fpots, twice
^ year, and no more, might be feen to be made in right linesj let
fuppofe this point O [in f 4.] to be the centre of the grand
Orb, or, if you will, of the Ecliptick, and likcwife alfo of the
Globe of the Sun it felf ; of which, by reafon of the great di-
ftance that is between it and the Earth, we that live upon the
Earth, may fuppofe that we fee the one half: we will therefore
defcnbe this circle A B C D about the faid centre O, which repre-
lenteth unto us the extream term that divideth and feparates the
Hemifphere of the Sun that is apparent to us, from the other that
IS occult. And becaule that our eye, no lefTe than the centre of
Earth, isundcrftoodno be in the plane of the Ecliptick, in
^^ichis likewiie the centre of the Sun, therefore, if we fliould
*,^^^y to our felves the body of the Sun to be cut thorow by the
|aid plane, the feaion will appe.ir to our eye a right line, which
l^^be Bod, and upon that a perpendicular being let fall AOC,
*^Mbe the Axis of the faid Ecliptick, and of the annual mo-
tion of the Tcrreftrial Globe. Let us next fuppofe the Solar body
Without changing centred to revolve in it felf, not about the

. - -..angv^.f- y ^

^.^is A O C f which is the ereft Axis upon the plane of the E
^^Ptick) but about one fomewhat inclined, which let be this
^^t. the which fixed and unchangeable Axis maintameth it felf
Perpetually in the fame inclination and direaion towards the
lame pomts of the Firmament, and of the Univerlc. And be-
^Ufe, ill the revolutions of the Solar Globe, each point of its fu-
P^J^ficies (the Poie^ excepted) defcribeth the circumference of ^

Rr a circle

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

31^ Galilmus , hisSyfleme.

circle, either bigger or lefler, according as it is more or leffe re-
mote from the faid Poles, let us take the point F, equally diftant
from them, and draw the diameter F O G, which fliall be perpen-
dicular to the Axis E I, and fliall be the diameter of the grand
circle deicribed about the Poles EL Suppofing not that tbe
Earth, and we with her be in fuch a place of the Ecliptick, that
the Hemifpherc of the Sun to us apparent is determin'd or bound-
ed by the circle A B C D, which paffing (as it alwayes doth) by
the Poles A C, paffcth alfoby E I. It is manifeft, that the grand
circle, whofe diameter is FG, (hall be ereft to the circle A B C D,
to which the ray that from our eye falleth upon the centre 0, is
perpendicular ; fo that the faid ray falleth upon the plane of
the crcle, whofe p.ameter is F G, and therefore its circumference
will appear to us a right line, and the felf fame with F G, where-
upon if there Ihould be in the point F, a fpot , it comming after-
wards to be carried about by the Solar converfion, would, upo"
thefurface of the Sun, trace out the circumference of that cir-
cle, which feems to us a right line. Its courfe or paffage wiH
therefore feem ftraight. And ftraight alfo will the motion of tb«
other Ipots appear, which in the faid revolution fliall 'dcfcribe le^'
fer circles, as being all parallel to the greater, and to out eye
placed at animmenledifiancc from them. Now if you do but
confider how that after the Earth (hall in fix moneths have 10"
thorow half the grand Orb, and lhall be fituate oppofite to th*'
Hemilphere of the Sun, which is now occult unto us fo as tba*

fJme A B7n %T ^"n!''^" f-n -ay be the fe^

lame AB CD, which alfo lhall paffe by the PoS EU yo«
fliall umlerttand that the fame will ^vene L tt cou ffs of >
fpots, as before, to wit, that all will appear to be m^d7hv rigl"
,nes^ But bccaufe that that accident Ses Tot Jla^fte ot
iy when the terminator or boundary p,fleth by the Poles E*'
and the faid terminator from moment to moment, by meaner o
u't ^TaJTT' '^^^""""ally altereth, therefore its pa<^
fjgc by the fixed Poles E I, fljall be momentary, and confequcnf

'^"l^' ^^^'^ the^motions ofV

fpots fliall appear ftra.ght. From what hath been hitherto fpokefl
one may comprehend alfo how that the apparition and beginnif
of the motion of the fpots from the part F, proceeding to^^^*
G, their paffages or courfcsare from the left hand, afcending to-
wards the right ; but the Earth being placed in the part <lia«>^'
jrically oppofite the appearance of the fpots about G, /hall 0}
to the left hand of the beholder, but the paflige lhall be Jef-
te be"# ^^''^ ^ Let us now defcribc theEartb

»nd lis P^"/«^?" diftant from its prefcnt ft*;;'

<lriw, as in the other figure, the terminator A B C I>'

I A t O G U E

in.

317

lane

in Fig, 5 .] and the Axis, as before A C, by which t] ^
our Meridian would paffe, in which plane fhould alfo be the
Axis of the Suns revolution? with its Poles, one towards us, that
is, in the apparent Hemilphere, which Pole we will reprefent by
the point and the other fliall fall in the occult Hemilphere,
and I mark it I. Inclining therefore the Axis E I, with the fupe-
riour part E, towards us , the great circle defcribed by the Sun*
converfion, (hall be this B F D G, whofe half by us fcen , name-
'y B F D, fliall no longer feem unto us a right line, by reafon the
Poles E I arc not in the circumference A B C D, but lhall appear
mcurvated, and with its convexity towards the inferiour part C.
•^"d it is manifeft, that the fame will appear in all the leffer cir-
^'es parallel to the fame B F D. It is to be underftood alfo, that
when the Earth (hall be diametrically oppolite to this ftate, fo
that it fccth the other Hemifphere of the Sun, which now is hid,
fliall of the faid great circle behold the part D G B incurved,
With its convexity towards the fupcriour part A , and the cour-
fes of fpots in thefe conftitutions fliall be firft, by the arch
D^and afterwards by the other D G B, and the firft appari-
tions and ultimate occultations made about the points B and D,
lhall be equilibrated, ^ind not thofe that arc more or lefTe eleva-
ted than thefe. But if we conftitute the Earth in fuch a place
of the Ecliptick, that neither the boundary A B C D, nor the
Meridian AC, palTeth by the Poles of the Axis E I, as I will fliew
you anon, drawing this other Figure \jui%,Fig,6r^ wherein the
apparent or vifible Pole E falleth between the arch of the termi-
i^ator A. B, and the feftion of the Mf ridian A C ^ the diameter
of the great circle fliall be F O G, and the apparent femicircle
. N G, and the occult femicircle G S F, the one incurvated with
Its convexity N towards the inferiour part, and the other alfo
l^^nding with its convexity S towards the upper part of the Sun.
T'he ingreflTions and exitionsof the fpots, that is, the termes F
^^dG fliall not be librated, as the two others B and D ^ but F
ftall be lower, and'G higher : but yet with lelfer diflPerence
^^^n in the firft Figure. The arch alfo F N G fliall be incurva-
J5^> but not fo much as the precedent B F D i fo that in this po-
htioa the paffages or motions of the fpots fliall be afcendcnt
trom the left fide F, towards the right G, and fliall be made by
curved lines. And imagining the Eat th to be conftituted m the
P^fition diametrically oppofite fo that the Hemifphere of the
^i^n, ^vhich was before the occult, may be the apparent, and ter-
minated by fame boundary A BCD, it will be manifeftly
Jiicerncd, that the courfe of the fpots fliall be by the arch G S F,
^ginnmgfroin the upper point G, which fliall then be likewife^
^ «^om the left hand of the beholder, and going to determine, 6t(^
■ cending

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

giS G. G A L I L ^ u s, his Syjleme.

fcending towards the right , in the point F. What I have hir
therto (aid , being undcrftood , 1 beUeve that there remains no
difficulty in conceiving how from the paffingof the terminator ot
the Solar Hemifpheres by the . Poles of the Suns converfion, or
neer or far from the fame, do arife all the differences in the appa: ^
rent courfes of the fpots^ fo that by how much the more thofc Poks
fliall be remote from the faid terminator,by fo much the more (hall
thofe courfes be incurvated , and leffe oblique h whereupon at
the fame diftance , that is, when thofe Poles are in the feftion of
the Meridian, the incurvation is reduced to the grcateft , but the
obliquity to the leaft , tlM is to JEquilibr in m ^ as the fecond of
thefe three laft figures [ 'z/zz.- Fig. 5.] demonftrateth. On the
contrary 5 when the Poles are in the terminator, as the firftof
thefe three figures [-z/ix. Fig. 4.] iheweth the inclination is at
the greateft , but the incurvation at the leaft , and reduced to
rcftitudc. The terminator departing from the Poles , the curvity
begins to grow fenfible , the obliquity all the way encreafing?
and the inclination growing leffer.

Thefe are thofe admirable and extravagant mutations, that mjf
Gueft told me would from time to time appear in the progrefl^^
of the Solar fpots , if fo be it (hould be true that the annual
tion belonged to the Earth, and, that the Sun being conftitutea
in the centre of the Ecliptick , vyerc revolved in it felf upon an
Axis , not ereft , but inclined to the Plane of the faid Eclip-
tick.

Sagr. I do now very well apprehend thefe confequcnces,
and believe that they will be^better imprinted in my fancy, when
•I (hall come to reflcft upon them , accommodating a Globe to
thofe inclinations , and then beholding them from feveral pl^*
ces. It now remains that you tell us what followed afterW^r^^
touching the event of thefe imaginary confequences.
The events h- S A L V, It came to paffe thereupon , that continuing many
%t^Zhu)rthc veral moneths to make moft accurate obfervations, noting down
}redi^i»ns- with great exaftueffc the courfes or tranfitions of fundry fpots at
divers times of the year , we found the events punSually to cor-
refpond to the prediftions.

S a g:r. SimpliciHs^ if this which ^'^/•z/i^^i^ faith be truc^ (^^^
canwe diftrnft him upon his word) the Ftolomeans and Ari^^'.
^f/e^jw/ hadneed of folid arguments, ftrong conjeftiires ?
Well grounded experiments to counterpoife an objeftion
tnuch weight , and to fupport their opinion from its fin^l
throw.

S I m; p. Fair and foftly good Sir , for haply you may ^^^^^j

be got fb far as you perfwade your felf you are gone.

though I am not an abfolute mafter of the fubjeft of that narr^-

tion

Dialogue III.

tion given us by Salviatm \ yet do I not find that my Logick,
^Mft I have a regard to form , teacheth me, that that kind of ar-
gumentation affords me any neceffary reafon to conclude in fa-
vour of xh^Co^ernkan Hypothefis , that is , of the ftability^ of
the Sun in the centre of the Zodiack , and of the mobility of
the 6arth und^r its circumference. For although it be true, that
the faid converfion of the Sun , and cirnition of the Earth being
granted , there be a neceflity of difcerning fuch and fuch ftrange
extravagancies as thefe in the fpots of the Sun, yet doth it not
follow xh2it 2ix^\^gftr confer [urn , from finding fuch like un-
iifual accidents in the Sun , one muft of necflity conclude the
Earth to move by the circumference , and the Sun to be placed
the centre of the Zodiack. For who fhall affertain me that the
like irregularities may not as well be vifible in the Sun, it being
"Moveable by the Ecliptick , to the inhabitants of the Earth, it
being alfo immoveable in the centre of the fame ? Unlefle you
^emonftrate to me, .that there can be no reafon given for that ap-
P^sirance , when the Sun is made moveable, and the Earth ftable,
I will not alter my opinion and belief that the Sun moveth , and
the Earth ftandeth ftill. . , , ,

S A G R. Simplicim behaveth himfelf very bravely , and argueth
Very fubtilly in defence of the caufe ot Arifloth and Ptolomy j
andif Imay fpeakthe truth, mythinks that the convcrfation of
%ahiatus , though it have been but of fmall continuance, hath
'^uch farthered him in difcourfing filogiftically. An cffeft; which
I know to be wrought in others as well as him. But as to finding
and Judging whether competent reafon maybe rendered of the
apparent exorbitancies and irregularities in the motions of the
fpots , fuppofing the Earth to be immoveable , and the Sun
naoveable , I (hall cxpeft that Sal'viatus manifeft his opinionto
, for it is very probable that he he hath confidercd of the
^*nie , and colleftcd together whatever maybe faid upon the
P^int. '■

S A L v.- I have often thought thereon , and alfo difcourfed
thereof with my Friend and Gueft afore-named ^ and touching
^hat is to be produced by Philofophers and Aftronomers , in de-
fence of the ancient Syfteme , we are on one hand certain , cer-
^^^"Ifay, that the true and pure Ferif^^^t/^V laughing at fuch
employ themfelves in fuch, to their thinking , jnfipd toole-
'Au \ ^etifure all thcle Thanomena to be vain lUufions of the
and in this manner will with little trouble free them-
Selves from the obligation of ftiidyingany more upon the tame,
^gam, as to the Aftronomical Philofophers, after we have with
iome diligence weighed that whix:h may be alkdged as a mean
between thofe two others , we have not been able to find out a«i

anfwer

Though the ak-
r.uat motion ^Jfigf*'
ed to the Earth an*
[rverthtothe Phx-
nomena of the fo*
Ur [pots^ yet doth
it not follow by com"
ver^on that from
the phenomena of
the fpots one may
irfsr the anvttal
Motion to Men£ t»
the Earth,

The Pure Peri-
patetick Philofo'
fhers rvilllattghat
the fpots and their
Phaenomena , st
illnfions of the
Chryfials in the
TeUfcope,

Ci . G A L I L u bis Syjlcme.

fwer that fafficeth to fatisfie at once the courfe of thefpots,

once

1 will explain unto you lo
you may judge thereon as

uch

Jf the Earth be
immoveable in the
centre of the Zodt-
ack^y there mufibe
afcribed to the Stin
four ftveral moti-
ons ^ as i* declared
at ItHgtk,

and the difcourfc of the Mind
as I remember thereof , that f
bell unto you.

Suppofing that the apparent motions of the Solar fpots are the
fame with thofe that have been above declared , and fuppofing t'jf
Earth to be immoveable in the centre of the Ecliptick , in whore
circumference let the center of the Sun be placed ^ it is neceflary
that of all the differences that are feen in thofe motions, the cau-
fes do refide in the motions that are in the body of the Sun
Which in the firft place muft necelTarily revolve in it felf i}\ ^'
about its own axis ) carrying the fpots along therewith , which
fpots have been fuppofed , yea and proved to adhere to the So-
lar fuperficies. It muft fccondly be confeft, that the Axis of the
Solar converfion is not parallel to the Axis of the Ecliptick , that
is as much as to fay , that it is not perpendicularly erefted up^^
the Plane of the Ecliptick , becaufe if it were fo ^ the courfes ana
exitions of thofe fpots would feem to be made by right lines p^"
rallel to the Ecliptick. The faid Axis therefore is inclining ?
regard the faid courfes are for the moft part made by curve in^f*
It will be necelfary in the third place to grant that the inclina^''
on of this Axis is not fixed , and continually extended toWar^J^
one and the tame point of the Univerfe , but rather that it aotn
alwayes from moment to moment go changing its direfiion j
if the pendency fliould always look towards the fcif fame point>
the courfes of the fpots would never change appearance but
appearing at one time either right or curved 5 bending upwaf ds
or downwards , afcending or defcending , they would appcaf
the fame at all times. It is therefore necelTary to fay , that tb^
faid Axis is convertible ; and is fometimes found to be in
Plane of the circle that is extreme, terminate? or of the vifi''^^
Hemifphere , I mean at fuch time as the courfes of the fp^^^
feem to be made in right lines , and more than ever pcnden^)
which happeneth twice a year ^ and at other times found to be
the Plane of the Meridian of the Obfervator , in fuch fort tb^^
one of its Poles falleth in the vifible Hemifphere of the Sun , an^
the other in the occult i and both of them remote from the eX^
treme points , or we may fay , from the poles of another Axi^
the Sun 5 which is parallel to the Axis of the Ecliptick j (y^^^^ ^
fecond Axis muft neceffarily be affigned to the Solar Globe)
mote, I fay, as far as the inclination of the Axis of the revolutio^
of the fpots doth import ^ and moreover that the Pole falUng^ ^
the apparent Hemifphere , is one while in the fuperiour;» anot e
while in the inferiour part thereof h for that it muftbefo> ^ ^
courfes themfelves do manifeftly evince at fuch tiroe as the/ ^\

Dialogue HI.

521

their

eft

one while with

cLirvity

heir convexity towards the^ upper part, and another while
towards the lower part of the Solar Difcm, Andbecaufe
thofe pofitions are in continuall alteration , making the in-
clinations and incurvations now greater, now leffer, and fomc-
times reduce thcmfelves, the tirft Ibrt to perfcfl: libration, and
the fecond to pci feft perpendicakrity,it is neceffary to affert that
thefelf fame Axis of the monethly revolution of the fpots hath
a particular revolution of its own, whereby its Poles dcfcribe
two circles about the Poles of another Axis, which for that rea-
fon ought(aslhavefaid)tobea(rigned tothc Sun, the feniidi-
atncter of which circles anfwereth to the quantity of the incli-
nation of the faid Axis. And it is neceffary, that the time of its
Period be a year ", for that fuch is the time in which all the ap-
P^arances and differences in the courfes of the fpots do return.
And that the revolution of this Axis, is made about the Poles of
Ac other Axis parallel to that of the Ecliptick, & not about other
points, the grcateft inclinations and greateft incurvations, which
are always of the fame bigncfs, do clearly prove. So that finally, to
maintain the Earth fixed in the centre, it will be neceffary to af-
fien to the Sun, two motions about its own centre, upon two fevc-
ral Axes, one of which finiflieth its converfion in a year, and the
other in Icffe than a moneth ^ which affumption fcena^th, to my
underftanding, very hard, and almoft impoffible j and this de-
pendeth oa the ncceffity of afcribing to the faid Solar body two
other motions about the Earth upon different Axes, defcribing
>ivith one the Ecliptick in a year, and with the other forming fpi-
rals , or circles parallel to the EquinoSial one every day :
whereupon that third motion which ought to be affigned to the
Solar Clobc about its own centre ( I mean not that almoft
monethly, which carrieth the fpots about, but I fpeak of that o-
Aer which ouaht to paffe thorow the Axi? and Poles^of this
"lonethly onef ought not, for any reafon that I lee, to finifli its
I^eriod rather in a year, as depending on the annual motion by
Ecliptick than in twenty four hours, as dcpcndmg on the
^i^^nal motion upon the Poles of the Equinoaial. ^ ^^^^
^hatl now fpeak is very obfcure, but I fiiall make it plain unto
you, when we come to ipcak of the third motion annual, aiUgn^
f d by Coferntcm, ,0 the Earth. Now if thefe four motions, fo
^"^^ngruous with each other, (all which it would be neceffary to
^ffign to the felf iame body of the Sun) may be reduced to one
fole and fuT^pie motion, affigned the Sun upon an Axis that never
changeth pofition and that without innovating any thing in the
motions for fo many other caufes affigned to the Terreftrial
Globe, may foeafilv falve fomany extravagant appearances tfx
^ S f

G. G A L I L ^ u s ^ his Syfleme.

the motions of the Solar fpots, it feemeth* really that fuch an
Hypothefis ought not to be reje&ed.

This, Smplicius^ is all that came into the minds of our friend
and my felf, that could be allcdged in explanation of this Ph^tJO'
menonhy the Copernicans^ and by the Ptolom^ans^ in defence
of their opinions. Do you inferre froim thence what your judg-
ment perfwades you.

Simp. I acknowledge my felf unable to interpofc iit fo ini'
portant a decifion : And, as to my particular thoughts, I ^^i^l
ftand neutral , and yet nevertheleffe I hope that a time will
come, when our minds being illumin'd by more lofty contempl^"
tions than thefe our humane reafonings, we (hall be awakened
and freed from that mift which now is fo great an hinderance to
our fight.

S A G R. Excellent and pious is the counfel taken by Simple'
rim J and worthy to be entertained and followed by all, as that
which being derived from the higheft wifdome and fupreaineft
authority, may onely, with fecurity be received. But yet fo
as humane reafon is permitted to penetrate, confining my ^^}^
within the bounds of con jeftures, and probable reafons, I
fay a little more refolutcly than Simplkim doth, that ainoU#
all the ingenuous fubtilties I ever heard, I have never met ^^^^JJ
any thing o£ greater admiration to my intellefl:, nor that
more abfolutely captivated my judgment, (alwayes excepri^^S
pure Geometrical and Arithmetical Demonftrations) than theft
twoconjeaures taken, the one from the ftations and retrograda'
tions of the five Planets, and the other from thefe irregularities oi
the motions of the Solar fpots .* and bccaufe they feem to me
cafily and clearly to aflign the true reafon of fo extravagant
pearances, /hewing as if they were but one fole fimple moti^^'
mixed with fo many others, fimple likewife, but different fr^?
each other, without introducing any difficulty, rather with ob^J'
ating thofe that accompany the other Hypothefis ^ I am thii^l^'
ing that I may rationally conclude, that thofe who contumacy'
oufly withftand this Do&ine, either never heard, or never un'
dcrftood, thefe fo convincing arguments.

S A L V. I will not afcribe unto them the title cithjer of
vincing, or non-convincing j in regard my intention is not,
have fcveral times told you, to refolve any thing upon fo ,1
queftion, but onely to propofe thofe natural and Aftro^ion^^^^^
reafons, which, for the one and other Syfteme, may be produce
W me, leaving the determination to others ; which determin^^^'

cannot at laft, but be very manifeft ; for one of the two p^'^'
tions being of necefiity to be true, and the other of necefllty
be lalfe, it is a thing impoffible that (alwayes confining our felv^^

Dl ALOGUE. HI.

within the Umics of humane doftrinc''

and its ti:lc Dtf-
qui fit tones Ada-

Vne Eclip:ici

-iumiiii iHuov^i 1......-"^ ■) ^'^^ rcafons alledged for

theuurHypo fcould not manifeft themfelvesas concludent
as ihoie for the contrary vain and inefFeanal. ^

S A G 1 1 will be time therefore, that we hear the objections
of the little Book of ^ Conclufions Difquifitions which Sim^h- ^^(^'^^^^^^

cms did brina with him. true name of this

S.M,. Here is the Book, and this is the phce where the Au- -f-''^Au-.
thorfirft briefly delcribeth the Syfteme according ^^^^ sch,ir,nu.,

to the Hypothefis of Copernicm, faying, 7erram igitur una cum -ts ti:lc D.f-
Liina, totoqne hoc elementari mundo Copernicus, &c. ^

Salv. Forbear a little, Simplkitts, for inethinks that this
Autlwiir, in this firft entrance, ftiews hinifelf to be but very ill
^erft ii, the Hypothefis which he gocth about to confute, in re-
gard, he faith that Copernicm ms^kcth the Earth, together with
the Moon, to defcribe the * grand Orb in a year moving from
Eaft to Weft i a thing that as it is falfe and impoffible, lo was it •
never affirmed by Copernicus, who rather maketh it to more the
contrary way, I mean from Weft to Eaft, that is, accordmg to
the order of the Signes ; whereupon we come to think the iame
to be the annual motion of the Sun, conftituted immoveable in
the centre of the Zodiack. See the too adventurous confidence
of this man ; to undertake the coofqtation of anothcrs Doanne>
and yet to be ignorant of the priii^ary fundaraentalsi upon which
his advcrfary layeththe greateft and wioft important part of all
the Fabrick. This is a bad beginning to gain himfelt credit
With his Reader i but let us go oD.j onLl; u.^,^ ,u ;

; Simp. Having explained the Univerfal Syfteme, he beginneth
to propoiui4 his objeaions againft this annual motion : And
% firft arc thefe, which he citeth Ironically, and in derifiori , ot ^
Copernicus and of his followers, writing that in this phantall|cal s^k. A"-
fcothefis' of the World one Jmuft -"^-^X "^'"X'^y ^IVcoT^'
«roffe abfurditiesi namely, that the Sun, Venus, and U r^ury ,f
% below the Earth -, and that grave matters .f n«-%:.^P-
rTvards, and ihe light downwards •, and that Cfc^j^, our Lord .^nd
Redeemer, kended into Hel!,and defcended into Heaven, wkn
^-approache4 towards ^^^un, and that wh,n 7./«-»fc^^^
™*udedthe;Sun to ftand ftill, theE.rth ^^^^ f^^^^'J^^Z
nioved a contrary way to that of the Earth -, and that whej the
.sinciL^ the Lr^h runneth through Capr.crrn^ a^that
^he Hy.^j Winter) Signes imke the ^iin^cr , .nd t^^
fj't^-/ Winters and that the Stars do '^^/^^^^^^^^^^^^^
Earth, but the Earth to the Stars ; and, that tk Eait bcgm-
ncth in the Weft, and the Weft in the Eaft, and, in a word,
tliatalmpft the whole courfe of the World IS inverted. .

. Sa Lv. Every thing pleafeth me,except U be his havmg.xntei>
'toth Sf a B™*

agtixjt CopCrai'
cus.

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

3?4

Suppofing the
dnnuMl motion t0
belong to the£arthy
it foliowetby that
one fixed Star-, is
bigger than the
vfhelc grand Orb,

Tycho his e^r-
gument grounded
upen 4 falfe Hjfo^
thefts.

LitigioHS L^yvyers
that are entertain'
ed in an ill cattfty
keef clofe to fame
exvrcffien fallen
from the adverfe
farty at H»4VfMres,

G. G A L I L i^: u s ^ his Syjieme.

mixed places out of thcfacred Scriptures(alwaycs venerable,and
toberever'd^ amongU thcfe, but two fcurriloiis fooleries, and
attempting to wound with holy Weapons , thofe who Philofo-
phating in jeft, and for dlvertifement , neither affirm nor deny,
but , fomc prefuppofals and pofitions being aflumed, do famili-
arly argue.

S 1 M p. Truth is, he hath difpleafed me alfo, and that not a
little *, and efpecially, by adding prefently after that, howbeit,
the CopernichiHs anfwer, though but very impertinently to thefe
and fuch like other reafonsjyet can they not reconcile nor anfwer
thofe things that follow.

S A L V. This is worfe than all the reft j for he prctcndeth to
have things more efficacious and concludent than the Authorities
of thefacred Leaves j But I pray you, let us reverence them,
and palTe on to natural and humane reafons : and yet if he give
usamongfthis natural arguments, things of no more folidity,
than thofe hitherto alleadged, we may wholly decline this undcf-
taking, for I as to my own particular, do not think it fit to fpen^l
words in anfwering fuch trifling impertincncies. And as to what
he faith, that the Copermcans anfwer to thefe objeSions, it
moft falfe, nor may it be thought, that any man fliould fet
felf to waft his time fo unprofltably.

S I M p. I concur with yciu in the fame judgement j therefo^^

let us hear the: otfrer inftanccs that he brings, as much ftrong^'

And obfcrve here, how he Vvith very exaft computations conclu*

eth, that ,f the grand Orb of the Earth, or the ecliptick,in which

Ct;p.mr;^makethittorun'in a year round the Siin, ftould be

as it were, infenfible, in refpeft of the immenfuie of the Starry

Spb^d , -according as the faid Copernicm , faith it is to be fuF

poled. It would be neceffary to grant and confirm,that the fi^ce^l

ffom us, an unconceivable diftancc, andtb^^

the iefler of them, were bigger than the whole grand Orb afor^"

faid,^ and fome other much bigger than the whole Sphere of S^'

\^^n.y^^^ unimaginable,
iiiciredple* '

A .L V. I haye heretofore feen fuch another ob jedion brought
by Tj^i. agaiijift Coftrnicus^ apd this is not the firft time that I
hav9 difcovered the fallacy, bir, to fay better, the fallacies of f*^^
ArgiiiHemtatioh,foundcd upon a moft falfe Hypothefis,and upon
a Pi9p0fltion of the faid Copernicus, ynderftood by his ad^^rfa-
• ^ Y^^J. \ f^^^ punfiual a nicity, according to the prafiife oi thofr
P%ders, who finding tht flaw to be in the very merit of theit
caufe, ' keep to fome one word, fallen unawares from the contra-
^ f ^^^^ ^ .^n^J fly out into loud and tedious defcantstipon that-
^ y^*^*^ better information i CopernicHs having declared

,^ thofe

DlALOGU E 111. p$

thofe admirable confequeiices which are derived from the Earths » or progrcfllons.
annual motion^to the other Planets^that is to fay, of the direfti- The Af parent
ons and retrogradations of the three uppermoft in particular ; he tTjTilZT'l
fub)oyneth,that this apparent mutation ("which is difcerned more ir>[cnfibie in the
m Mars thdin 'm J Hpiter, by reafon y^/f/fer is more remote, and fi-^'^^^^^'-.
Jet leffe in 5^t^ir//, by reafon it is more remote than y«j?i/t?r ) in
the fixed Stars, did remain imperceptible, by reafon of their
immenfe remoteneffe from us, in comparifon of the diftances of
Jupiter or Saturn. Here the Adverfaries of this opinion rife up,
and fuppofing that fore-named imperceptibility of Copernicus^ as
if it had been taken by him, for a real and abfolute thing of no-
ting, and adding, that a fixed Star of one of the lefl^er magni-
tudes, if notwithftanding perceptible, feeing that it cometh un-
der the Icnee of feeing, they go on to calculate with the inter-
vention of other falfe affumptions, and concluding that it is necef-
fary by the Copernican Doarine,to admit, that a fixed Star is much
'digger than the whole grand Orb. Now to difcover the vanity SHmUgthma
of this their whole proceeding,! Oiall (hew that a fixed Star of the fj[t m.^^JLtu
fixth magnitude, being fuppofcd to be no bigger than the Sun, nUig^er than the
one may thence conclude with true demonfl:rations, that the di- ^^^l^l^l^f'^^'^'^^l
ftance of the faid fixed Stars from us, cometh to be fo great, that f^/,'^ ^iLul^n
the annual motion of the Earth , which caufeth fo great and the fixed an is
notable variations in the Planets, appears fcarce obfcrvable in ^^'"''^"^A"/^^^-
them •, and at the fame time, I will diftinSly fliew the grofs
fallacies^ in the affumptionsof Copernicus his Adverfaries.

And firft of all, \ fuppofe with the faid Copernicus^ and alfo distance of

with his oppofers, tnat the Semidiameter of the grand Orb,which the s«», covtaineth
is the diftanceof the Earth from the Sun, containeth iao8 Semi- ^'^^f^^'"'^^-'^'*'
diameters of the faid Earth. Secondly, I premife with the allow-
ance aforefaid and of truth, that the * apparent diameter of the .* The Diameter
Suninitsmcak diftance, to be about half a degree, that is, 30. ''I'^l^''''^}''^ ^
^in. prim, which are 1800. feconds;^ that is, 108000. thirds.
Ahd becaufe the apparent Diameter of a fixed Star of the firft rhe Diameter
niagnitudt., isnomorethans-feconds, that is, 300. thirds,and

Diameter of a fixed Star of the fixth magnitude, 50. thirds, ttsde^andofoneof
iC^^dherdnisthegreatefterrourof the ^/ifi^C.^^^r^/.^^^There. the f^^f-^^^^^^^^
"Wre tlie Diameter of the Sun, coritaineth the Diameter ot a jrj,^^,,, ,f
'fi^ed Sta, ^l^^ (l^ch magnitdd^ 2^i6o timei. And therefore 5.«> W
'5*^^feeastarofthefixthigni wereTuppofed to be^eally
to the Sun, and not bigger, whichis the^ame as tofay, if
,f ^S^a were fo far removed , that its Diameter fliould feem to
beoneofithe :i 160.; parts of wha^itf now appeareth, itsdiltance
-Weight of it^ecefficy to be 2 1 60. tirtifes greater than now in effeft it
^1^, whicltis as much a^tofay, that the diftance of the fixed Stars
x>f the fixth magnitude is 2160. Semidiameters of the grand
' Orb.

^^(5 G. Galil^us, his Syjleme.

the ^ance of Orb. Ailcl bccaufc the diftancc of the Sun from the Earth, con-

4 fixed ftur of ti:e

tains by common confent 1 3o8. Semidiameters of the faid Earth,
fi>=,h magnu^dc, and the diftance of the fixed Stars ( as hath been faid ) ti6o.
flsrhewg ftippofed Scmediatneters ot the grand Orb, therefore the Scmediameter oi
t9 be equal xo the ^j^^ Earth IS much greater (that is ahnoft double) in comparifon
of the grand Orb, than the Senpiediameter of the grand Orb, ii^
Intkefi^-edflMTs relation to the dlftaucc of the Starry Sphae re j and therefore the
Tea'^'^clufedT variation of afpea in the fixed Stars, caufcdbythe Diameter of
the grand. O'b^ ts the grand Orb, can be but little more obiervablc^than that which
intie more then is obfetved in the Sun, occafionedby the Semediameter of the

that ca.tfed by i
EArih in the Snn, Earth.

S A G R. This is a great tall for the firft ftep.
S A L V. It is doubtlefTe an errour ^ for a fixed Star of the fijctb
A flar of the magnitude, which by the computation of this Authour, ought?
iliofZhT.to for the upholding the propofition of Copcrnicm, to be as big
andihe ^mhonr the whole grand Orb, onely by fuppofing it equal to the Sun?

'il^w "^^^^"^ '^^^ ^'^^^ hundred and fix milionth pafC

'dVrjnd 7x of the faid grand Orb,maketh the ftarry Sphere fo great and higl^
Th^In^Z"^*^^'"^ as fufficeth to overthrow the inftance brought againft the faid
pernicHS.

Sagr. Favour me with this computation. ^
S A L V. The fupputation is eafie and (hort. The Diameter
The tempatAti. the Sun, IS clcvcn femediameters of the Earth, and the Dian^^tef
OH the magni. of the grand Orb, contains a^id.ofthofe fame femediametef^j
'sttftnr!fp^att ^y^^^ afcent of both parties i fo that the Diameter of the faid
the grand Orb. Orb, contains the Suns Diameter 220. times very near. Ai^^
becaufc the Spheres are to one another, as tl\e Cubes of their Di'
ameters,lct us make the Cube of ^lao. which is 1064^0000. an^l
we fhall have the grand Orb, an hundred and fix millions, foP^
hundred and eighty thou fand times bigger than the Sun, to vvW^*
grand Orb, a ftar of the fixth magnitude, ought to^be cqual?^^'
cording to the affertion of ehist Authour. - ,

Saga. The errour then of thefe men, confiftethin being
treamly miftakea,. in taiung^tjie apparent Diameter of the fi^^
Stars; .of .obinin^hm dixii -jfb "io J j
S A L V. This IS one, b^t not thcodely errour of them h
iXcommofier. indeed, I do very much admire how fo many Jllrotiomcrs,
aronomers,/.«cA- Very tamous, as are Aljdgranm-, Albategnpfs^7ebi'^^^'

^^^fthe^a^*"^^^^' much moremodernly the.l^c/jo'j^ and C/^i/z^j'^, and in f*^^||'^
<>n ^ all thepredecelTors of our y^ffi^i^wijWjft^ have beenf^^^^

miftaken, in determining the magnitudes of all the Sut^y ^
fixed as moveable, the two Luminaries excepted out of that

and that they have not taken any heed to the adventit^^.^^
irradiations tb'lt deceitfully reprefent them an hundred and ino
times bigger, , th%ft^ when.they are beheld, . without thofc cal>i^^^

DialogueIIL 327

ous rayes, nor can this their inadvertency be exculed, in regard
that it was in their power to have beheld them at their pleaTure
without thole treffes, which is done, by looking upon them at
their firft appearance in the evening, or their laft occultation in . ,

-.1 , if- p J , .r^' r 1 n rr Wzms venders the

the comming on 01 day ^ and it none 01 the reit, yet Vennsy errour ofAftrcfio^
which oft times is feen at noon day, fo fmall, that one muft fliar-
pen the fight in difcerning it j and again, iri the following night, 7ffilr7Z*'xZf4'
feemeth a great flake of light, might advertife them of their fal-
'acy • for I will not believe that they thought the true Difcm to
t>e that which is feen in the obfcureft darknefTes, and not that
which is difcerned in the luminous Medium : for our lights, which
feen by night afar off appear great, and neer at hand fliew their
f^ue luftre to be terminate and fmall, might have eafily have
^ade them cautious ^ nay, if I may freely fpeak my thoughts, I
^bfolutely believe that none of them, no not T'ycho himfelf, fo
Accurate in handling Aftronomical Inftruments, and that fo great
^t^d accurate, without fparing very great coft in their conftru-
fiiorr, did ever go about to take and meafure the apparent dia-
"^^^ter of any Star, the Sun and Moon excepted ^ but I think,
^hat arbitrarily, and as we fay, with the eye, fome one erf the
Diore antient of them pronounced the thing to be fo and fo, and
that all that followed him afterwards, without more ado, kept
clofe to what the firft had faid *, for if any one of them had ap-
plied himfelf to have made fome new proof of the fame,he would
doubtleffe have difcovercd the fraud.

S A G R. But if they wanted the Telefcope, and you have al-
ready faid, that our Friend with that fame Inftrument came to
the knowledge of the truth, tliey ought to be cxcufed, and not
accufed of ignorance.

S A L V. This would hold good, if without the Telefcope the
^ufinefTe could not be effefted. Its true, that this Inftrument by
ftewingthe DifcHs of the Star naked, and magnified an hun-
^fed or a thoufand times, rendereth the operation much more ea-
fi^D but the fame thing may be done, although not altogether fo
c^aaiy^ without the Inftrument, and I have many times done

fame, and my method therein was this. 1 have caufed a rope ^^^^
be hanged towards fome Star, and I have made ufe of the ^he apparenc
Conftellation, called the Harp, which rifcth between the North diameter of ^fiar,
^nd^ North'eaft , and then by going towards and from . ^^^^^^^
^l^e Uid rope, interpofed between me and the Star, 1 have tound Latine cornm^ih^i
the place from whence the thickncfTe of the rope hath juft hid |^ ;o%> North-
the Star from me : this done, 1 have taken the diftance from the '"'^ '
^ye to the rope, which was one of the fides including the angle
^hat was compofed in the eye, and ^ which infifteth upon the * ,-...is ftibtca^
^i^ickneffe of the rope, and which is like, yea the fame with the ded by.

angle

angle in the Starry Sphere, that infifteth upon the diameter of
the Star, and by the proportion of the ropes thickncffe to the
diftancefrom the eye to the rope, by the table of Arches and
Chords, 1 have immediately found the quantity of the angle j u-
fmg all the while the wonted caution that is obferved in taking
angles fo acute, not to forme the concourfe of the vifivc ray^s
in the centre of the eye, where they are onely refrafied, but
beyond the eye, where really the pupils greatneffe maketh theifl
to concur.

Sagr. I apprehend this your cautelous procedure, albeit I
have a kind ot hgefitancy touching the fame, but that which fl^o^
puzzleth me is, that in this operation, if it be made in the dark
of night, mcthinks that youmeafure the diameter of the irradia-
ted DifcHSy and not the true and naked face of the Star.

S A L V. Not fo, Sir, for the rope in covering the naked body
of the Star, taketh away the rayes, which belong not to it, but
to our eye, of which it is deprived fo foon as the true Difcf^
thereof is hid 3 and in making the obfcrvation, you {hall fec,bov^
unexpe&dly a little cord will cover that reafonable big body^
light, which fcemed impoflible ro be hid, unlefTe it were with ^
much broader Screene : to meafure, in the next place, and c^^'
ftly to find out, how many of thofe thicknefTcs of[the rope iote>^'
pofe in the diftance between the faid rope and the eye, I take
onely one diameter of the rope, but laying many pieces of
fame together upon a Table, fo that they touch, I take with ^
pair of Compaffes the whole fpacc occupied by fifteen, or twen-
ty of them, and with that meafure I commenlurate the diftan^:^
before with another fmaller cord taken from the rope to the con-
courfe of the vifive rayes. And with this fufficiently-exaft op^'
ration I finde the apparent diameter of a fixed Star of the fi^^
magnitude, commonly cftccmed to be 2 min, pri and alfo 3
The diameter if f '^^'w. by Tycfc^? in his Ajironomical Letters^ cap, 167. tobe^^^
afixedfiar of the more than i^feconds^ which is one of the 24. or 2<5. parts of^h^^
SXfitj::. tbey have held it : fee now upon what groffe crrours their D'^
w/?. ftrincs are founded.

Sagr. I fee and comprehend this very well, but before
pafTe any further, I would propound the doubt that arif^^
me in the finding the concourfe [or interfeaion] of the vi'"^^
rayes beyond the eye, when obfervation is made of obje^^^^^^^'
prehended between very acute angles j and my fcruplc p^^^^^
from thinking, that the faid concourfe may be fometi^i^^^ ^^^^
remote, and Ibmetimes Icffe j and this not fo much, by tne^^^^
^f the greater or lelTcr magnitude of the objeftthat is beheld?

that in obferving objefls of the fame bigneffe , it ^^^^l
to me that the xoQCOurfe of the rayes, for certain other

Dialogue Hi.

fpcGs ought to be made more and Icffe remote from the eye.

Salv. I fee ah eady, whither the apprehenfion of Sagredm^
^ moft diligent obferver of Natures fecrets , tendcth h and I
^ould lay any wager, that amongft the thoufands that have ob-
served Cats to contraa and inlarge the pupils of their eyes very
much, there are not two, nor haply one that hath obfcrved the
like efFcftto be wrought by the pupils of men in feeing, whilft
the mediHm is much or little illumined, and that in the open light
the circlet of the pupil diminirticth confiderably : fo that in loo-
l^ing upon the face or Difcm of the Sun, it is reduced to a Imall-
nelieleffer than a grain of ^ Fanick^^ and in beholding objefts
that do not (hine, and are in a lefTe luminous nisdtnm^ it is inlar-

J to the blgneffe of a * Lintel or more ^ and in fumme this
^xpaufion and contraaion difFertth in more than decuple pro-
portion : From whence it is manifeft, that when the pupil is
dilated , it is necelTary that the angle of the rayes con-
courfe be more remote from the eye j which happeneth in be-
Wding ob)e£is little luminatcd. This is a Dodrine which Sa-
gredns hath, juft now, given me the hint of, whereby, if we
^^re to make a very exaft obfervation , and of great confe-
quence, wc are advertized to make the obfervation of that con-
courfe in the aft of the fame, or juft fuch another operation ^ but
in this our cafe, wherein we are to fliew the errour of JSirono^
niers-i this accuratenelTe is not neceffary : for though we fliould,
in favour of the contrary party, fuf«pofe the faid concourfe to be
made upon the pupil it felfjit would import little, their miftake
being lo great. I am not certain, Sagredus^ that this would have
^cen your objeftion.

^ A G R. It is the very fame, and I am glad that it was not al-
together without reafon, as your concurrence in the fame afTu-
tcth me but yet upon this occafion I would willingly hear what
may be taken to finde out the diftance of the concourfe of

vifual rayes. .
S L V. The method is very eafic, and this it is , I take two
^^«g^ labels of paper, one black, and the other white, and make
black half as broad as the white then I ftick up the white a-
g^i^ft a wall, and far from that I place the other upon a ftick, or
^ther lupport, at a diftance of fifteen or twenty yards, and rech-
r r L-/'-— f^^H*- line,

will

3^^

The circle of the
pupil of the eye en*
Ur^eth and corf
tra^etb*

fmall grai« like lo
Mill , I cake i: to
the fnme wich that
called Bird Seed.

support, at a aiuanv.c ui iulccu ' . .

^i"g from this, lecond another fuch a fpace in the fanie right lini
very nianifeft, that at the faid diftance the right lines wi
^^"^^^ that departing from the termes of the breadth of the
^hit^ piece, (hallpaffe clofebythe edges of the other label pla-
ced in theuiid-way ^ whence it followeth, that in cafe the eye
were placed in the point of the faid concourfe or interfcftion,
the black flip of paper in the midft would precifely hide the op-
^ T t pofitc

* Scrifce.

How to fi»d the
diji-gftceofrhersjs
Cffncoftrfe from the

d by courtesy of the Royal Library, Copenhage

G. G A L I L iE u s ^ M SjJJeme.

pofite bUnkjif the fight were made in one onely point , but if we
ftiould find, that the edges of the white cartel appear difcovered,
it fliall be a neceffary argument that the vifual rayes do not iffue
from one fole point. And to make the white label to be hid by
the black , it will be requifite to draw neerer with the eye *
Therefore, having approached fo neer, that the intermediate la-
bel covercth the other, and noted how much the required ap-
proximation was, the quantity of that approach fliall be the cer-
tain meafure, how much the true concourfe of the vifive rayes, is
remote from the eye in the faid operation, and we fliall moreover
have the diameter of the pupil, or of that circlet from whence
the vifive rayes proceed ; for it fliall be to the breadth of the
black paper, as is the difl:ance from the concourfe of the lines,
that are produced by the edges of the papers to the place where
the eye ftandeth, when it firft feeth the remote paper to be hii
by the intermediate one, as that diftancc is, I fay, to the diftancc
that is between thofe two papers. And therefore when
would, wich exafineflc, meafure the apparent diameter of a Star?
having made the obfervation in manner, as aforefaid, it would be
neceiTary to compare the diameter of the rope to the diameter of
the pupil j and having found *z^.g, the diameter of the rope to be
quadruple to that of the pupil, and the diftance of the eye frotn
the rope to be, for example, thirty yards, we would fay, that tb^
true concourfe of the lines produced from the ends or extrerni'
ties of the diameter of the ftar, by the extremities of the ^i^'
meter of the rope, doth fall out to be fourty yards remote (to^
the faid rope, for fo we fliall have obferved, as we ought, the pro-
portion between the diftance of the rope from the concourfe of
the faid lines, and the diftancc from the faid concourfe to th^
place of the eye, which ought to be the fame that is betv^^^^
the diameter of the rope, and diameter of the pupil.

S A G R. I have perfeftly underftood the whole bufinelTe, and
therefore let us hear what Simflicim hath to alledge in defence of
the Anti'Copernicans.

Simp. Albeit that grand and altogether incredible inconve'
jnience infifted upon by thefe adverfaries of Copernicus be mucfr
moderated and abated by the difcourfe of Sahiatus^ yet do 1
not think it weakened fo, as that it hath not ftrength enough
to foil this fame opinion. For, if I have rightly apprehended
chief and ultimate conclufion, in cafe, the ftars of the fixth
ritude were fuppofed to be as big as the Sun, (which yet I can
hardly think) yet it would ftill be true, that the grand Orb [^^
Hcliptick] would occafion a mutation and variation in the ft^^^^
Sphere, like to that which the femidiamcter of the Earth produ'
ceth in the Sun, which yet is obfervable h fo that neither that,

nor

i A L O G U E.

III.

5|s

i^ora Icfic mutation being difcerned in the fixed Stars, methihkis
that by this meansthe annual motion of the Earth is deftroyed
and Overthrown.

Salv. You might Very well fo conclude, SimpUcim^ if we
had nothing elfe to fay in behali of Copernicus : but we have
tnany things to al ledge that yet have noc been mentioned ^ and

to that ybur reply, nothing hindcrcth, but that we may fup-^
pofethe diftance of the fixed Stars to be yet much greater than
that which hath been allowed them, and you your felf, and who-
ever eUe will not derogate from the propofitions admitted by
^^^lomy\\.-.Q^2.tots^ muft needs grant it as a thing moft requifite
to fuppofe : he Starry Sphere to be very much bigger yet than
that which even now wc faid that it ought to be efteemed. For
^11 Aftronomcrs agreeing in this, that the caufe of the greater
^^rdity of the Revolutions of the Planets is, the majority of
^heir Spheres, and that therefore Saturn is more flow than Jh-
P^^^r^ and Jupiter than the Sun, for that the firft is to defcribe a
greater circle than the fecond, and that than this later, &c. con-
flicting that Saturn 'o-g* the altitude of whole Orb is nine times
higher than chat of the Sun, and that for that caufe the time of
^nc Revolution of S^^wr/?, is thirty times longer than thiat of a
copverfion of the San, in regaid that according to the Doftrine
of rf(?/(?wj, one converfion of the ftarry Sphere is finiflied in
36000. years, whereas that oi Sdtnrn is confummate in thirty,
^nd that of the Sun in one, arguing with a like proportion , and
%ing,if the Orb of %atnrn-i by reafon it is nine times bigger
^han that of the Sun, revolves in a time thirty times longer, by
converfion, how great ought that Orb to be, which revolves
36000. times more flowly } it fliall be found that the diftance of
the ftarry Sphere ou^^ht to be 10800 lemidiameters of the grand
^rb, which fliould b1,^ full five time? bigger than that, which cveh
^^W we computed it to be, in cafe that a fixed Star of the fixth
"^^gnitnde were equal to the Sun; Now fee how much leffer yeti
^^on this account, the variation occafioned in the faid Stars, by
J,^^annuarmotion of the Earth, ought to appear. And if at the
lame rate we would argue the diftance of the ftarry Sphere from
UpiUi, and from Uars, that would give it us to be 1 5000. and
J,his 27000 fcinidiameters of the grand Orb, to wit, the firft
/^ven, and the fecond twelve times bigger than what the itiag-
mtiide of the fixed Star, fuppofcd equal to the Sun, did make

. ^ ^ Mcthinks that to this might be anfwered, that the mo-
tJon of the ftany Sphere hath, fincef^^^/^'^;', been obfcrved not
to be fo flow as he accounted it ; yea, if 1 rniftake not, I have
'^eard that CopcrnicUs himfelf made the Obfervatidn, ^

Tt 2 SxtV.

t/4ll AFtror.o*
m:rs agree that
the greater magni-
titdes of the Qr^et
is the caufe »f thf
tardity of the con"
%erft»ns.

'By another frj>*
pojittffn taken fr«r»
Afironomers ^ the
diftance of the fix'
ed Stars is calcft-
Utsd to be logoo
femidiamettrs of
the grand Orb,

By the proportha
of inpkcT and of
Mars, the ftarry
^F^ere is found to
^^yet wg^e remetea

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

G. G A L 1 L /£ u s ^ Sjjieme.

S A L V. You fay very well *, but you alledge nothing in that
which may favour the caule of the Ftolo7n^ans in the leaft, who
did never yet rejeft the motion of 3<<ooo. years in the ftarry
Sphere, for that the faid tardity would make it too vaft and im-
menfe. For if that the faid immenfity was not to be fuppofed m
Nature, they ought before now to to have denied a converfion
fo flow as that it could not with good proportion adapt it leli?
fave onely to a Sphere of monftrous magnitude.

8 A G R. Pray you, '^al'vtatm^ let us lofe no more time in pf^'
ceeding, by the way of thefe proportions with people that are apt
to admit things moft dif-propoiiiou*4ce , lo that its impoA^'^^^
to win any thing upon them this way: and what more difpropox-
tionate proportion can be imagined than that which thefe ni^^
fwallow down, and admit, in that writing, that there cannot be ^
more convenient way to difpofe the Cccleftial Spheres, in ordeO
than to regulate them by the differences of the times of their p^'
riods, placing from one degree to another the more flow abo^^
the more fwift, when they have conftituted the Starry Sphe^^
higher than the reft, as being the floweft, they frame anoth^^^
higher, ftill than that^ and confequently greater, and make it
volvein twenty four hours, whilfl: thcrnext below, it moves n
round under jdooo. years ?

S A l V. I could wifli, SimpliciHSy that fufpending for a
the atfcfliion rhat you bear to the followers of your opinion, Y^.
would fincerely tell me, whether you think that they do in thei^
minds comprehend that magnitude, which they rejeft afterwarid^
as uncapablefor its immenfity tp be afcribed to the Univerfr
immi^^f^ ma^. Fpr I, as to my own part, think that they do not But believ^?
nitudes and num- that like as in the apprehenfion of numbers, when once a i^^^
t«>T/! ?r/.T begins to paffe thofe millions of millions, the imagination is f^:^
dtr^Mding, founded, and can no longer form a conceipt of the fame,

happens alfo in coniprehending immenfe magnitudes and ... .
ces j fo that there intervenes to the comprehenfion an effec*^
to that which befal)eth the femfc ^ For whileft that in a f^^f^
night L look towards the Stars, I judge, according to fenfe?
their diftance is but a few miles, and that the fixed Stars are not
jot more remote than Jupiter or Satnrnj nay than the ^^^^
But without more ado, confider the controvcrfies that h^^^
between the Aftronomers and Peripatetick Philofophers, ^"^^
occafion of the new Stars ofCajpopeja and of Sagittary.^ ^piilo-
ftronomers placing them amongft the fixed Stars, andt^^ .
fophers believing them to be below the Moon- So ^^^'^K ^^Upfc
fenfc to diftinguifli great diftances from the greateft, though t
be in reality many thoufand times greater than thofe. In a 4
I ask of ttee, O foolifli man ! Doth thy imagination compt^^^^^

I A L O G U E

III.

lich thou ;

Aat vaft magnitude of the llnivcrfe, which thou afterwards ^
^ft to be too immenfe ? If thou comprehendeft it j wilt thou
^oldthat'thy apprehcnfion cxtcndethit felf farther than the Di-
vine Power > wilt thou fay , that thou canft imagine greater
things than thofe which God can bring to paiTe ? But if thou
apprehendeft it not, why wilt thou palTe thy verdifl: upon things
beyond thy comprehenfion ?

Simp. All this is very well, nor can it be denied, but that
Heaven may in greatneffefurpafTe our imagination, as alfo that
God might have created it thoufands of times vafter than now it
is 5 but We ought not to grant anything to have been made in
^v^in, and to be idle in the LIniverfe. NoWjin that we fee this ad-
mirable order of the Planets, difpofed about the Earth in diftan-
CC5 proportionate for producing their effefts for our advantage,
^0 what purpofe is it to interpofe afterwards between the fublime
^rb of Saturn and the ftarry Sphere,a vaft vacancy, without any
that is fuperfluous, and to no purpofe > To what end ? For
whofc profit and advantage ?

S A L V. Methinks we arrogate too much to our felves, SimpU^
^iHs^ whilft we will have it, that the onely care of us, is the ad-
^equate work, and bound, beyond which the Divine Wifdome
and Power doth, or difpofeth of nothing. But I will not con-
fent, that we fliould fo much fhorten its hand, but defire that we
Wy content our felves with anaffurance that God and Nature
^re fo imployed in the governing of humane affairs, that they
.^ould not more apply themfelves thereto, although they had no
other care than onely that of mankind j and this, 1 think, 1 am
to make outby amoft pertinent and moft noble example,
taken from the operation of the Suns light, which whileft it at-
Vafteth thefe vapours, or fcorcheth that plant, it attraaeth, it
fcorcheththem,asif ithadnomore todo^ yea, in ripening that
^)^nch of grapes, nay that one finglc grape, it doth apply it felf
that it could not be more intenfe, if the fum of all its bufinefs
'^^d been the only maturation of that grape. Now if this grape
Jl.^^'eivethall that it is poflible for it to receive from the Sun, not
*"ffering the leaft injury by the Suns produdion of a thoufand
other effeds at the fame time ^ it would be either envy or tolly
to blame that ^rape, if it (hould think or wilh that the Sun would
^^^ly appropriate its rayes to its advantage. I am confident that
"^^^^ng is omitted by the Divine Providence, of what concemes
t*^^ government of humane affairs', but that there may not be
other things in the Univcrfe, that depend upon the fame infinite
Wiidome,lcannot,of my felf, by what my reafon holds forth
to.me, bring my f^lf to believe. However, if it were not fo,
J^t fhould I not forbear to believe the reafons hid before me by

God^ Sfature
do imfloj them"
felves in caring
for meny as tf the/
mindfd nothing

exMmpit of

gods cftre of man"
kind taken from
the Sun,

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

534 O. G A L I L /E u s> ^ij Syflcmcl

lohic more fubiime intelligence. In. the mean time if
fliould tell me, that an immente fpacc interpofed between the
Orbs of the Planets and the Starry Sphere , deprived of liars and
idle, would be vain and ufelelle , as likewife that fo greatan
immenfity for receipt of the fixed ftars, as exceed? our utiDoft
comprehenfion would be fuperfluous, 1 would reply, that it
raflmeflc to go about to make our fhallow reafon )udg of th^
Works of God , and to call vain and fuperfluous , whatfocv^^*
thing, in the Uniyerfe is not fubfervient to us.
It is reat r^ih ^ ^' "^^^ber , and I beheve you would fay better > ^'^^^

Keffe'^T'^le^fure wc know uot what IS fubfcrvicnt to us i and 1 hold it one of the
thMtohfufcrfiH' greateft vanities 5 yea follies , that can be in the World , tofty?
'^Vc7^l^"2'fol bec^ufelknownotofwhatufe J«/?/7<rror5'tf^«r//are to me, that
perceive t»he made therefore thcfc Planets arc fuperfluous , yea more , that there are
. no fuch things remm natura i when as , ohfoolidi man ^

know not fomuch as to what purpofe . the arteries, thegriftl^^^
the fpleen, the gall do fcrve \ nay 1 fliould not know that I hav^
a gall, fpleen, or kidneys , if in many defcfied Corps , they vvef^
not fliewn unto me 3 and then onely fliall I be able to know wh^^
the fplcen worketh in me , when it comes to be taken froni ni^*
To be able to know what this or that Cceleftial body worketh
fT'^'j! iTht ^"^ (fe'^i^g you will have it that all their influences direftth^^^
cometokjioro what Iclves to us) it would be icquifite to Fcmove that body for fot^^
infiuertce it hath time ^ and then whatfoever cfteft 1 fliould find wanting in mf>
upn w, would fay that it depended on that fl:ar. Moreover, who will p^J

fume to lay that the fpace which they call too vaftand ufelefl^
between Saturn and the fixed ftars, is void of other inm^^^^^
MMny things ^'^^^ } Muft it bc fo, becaufc wc do not fee them ? Then the iof
way het» Hcaticn^ Mc diceau Plane ts , and the companions of Saturn C2\xic firftiP;
that^are invipbh H^aven , wheu wc began to fee them , and not before ?

by; jthis rule the innumerable other fixed ftars had no exift^^^^
befprpthat men did look on them ? and the cloudy conftell^^f
Q^as called Nebulofce were at firft only white flakes, but afcerwaf^
with the Telefcope we made them to become conftellations P
many hivid and bright ftars, Oh prefumptious , rather ohralP
ignorance of man !

S n.v. It's to no purpofe. ^'j^reJ/^jtofally out any
tiief^. unprofitable exaggerations : Let us purfuc our inte^r .;
defigne of examining the validity of the reafons alledged i
ther fide , without determining any thing , remitting ^^^^^. ^
«ient thereof when we have done , to fuch as are more fc^^^^^^^^j
Returning therefore to our natural and humane difqnifiti^'j*^'
great, fmall, f^Y, ^tliat great, little, immenfe, fmall, are notabfolii^'
lTat\ttet] '"^^^'^^^ ^enns , fo that the felf fame thing compared v^'^^

divers others , may one while be called, immenfe , and anotn

DialogueIII.

^hile imperceptible, not to fay fmall. This being fo, I demand
relation to what the Starry Sphere of Copcr?ncm may be cal-
led over vaft. In my judgment It cannot be compared , or faid
to be fuch , unleffe it be in relation to fome other thing of the
ftme kind ^ now let us take the very leaft of the fame kind,
^hich ftiall be the Lunar Orb and if the Starry Orb may be fo
cenfured to be too big in refpeft to that of the Moon , eveiyo-
t^er magnitude that with like or greater proportion exceedeth
^nother of the fame kind , ought to be adjudged too vaft , and
lor the fame reafon to be denied that they are to be found in ihe
^^^Id j and thus an Elephant, and a Whale, (hall without more
^ o be condemned for Chymderas , and Poetical fifiions , be-
^aule that the one as being too vaft in relation to an Ant , which
^5 a Terreftrial animal , and the other in refpeQ: to the ''Gudgeon,
'iichisaFifh, and are certainly feen to be in rentm natnra^
^ould be too immeafurable i for without all difpute, the Ele-
Phant and Whale exceed the Ant and Gudgeon in a much great-
proportion than the Starry Sphere doth that of the Moon ,
although we fliould fancy the faid Sphere to be as big as the Co-
V^nicatt Syfteme makcth it. Moreover , how hugely big is the
Sphere of Jupiter , or that of Satitrn , defigned for a receptacle
but for one fingle ftar j and that very fmall in comparifon of one
of the fixed > Certainly if we fliould aifign to every one of the
fixed ftars for its receptacle fo great a part of the Worlds fpace,
Would be neceffary to make the Orb wherein fuch innumerable
"^iiltitudcs of them refide , very many thoufands of times big-
ger than that which ferveth the purpofe of Copernicus. Befides,
^ not you call a fixed ftar very fmall , 1 mean even one of the
^ apparent , and not one of thofe which rtiun our fight ^ and
. ^ We not call them fo in refpeft of the vaft fpace circumfufed ?
Now if the whole Starry Sphere were one entire lucid body j who
^^i,^cre,that doth not know that in an infinite fpace there might be
^%ned adiftancc fo great, as that the faid lucid Sphere might
'^om thence fliew as little , yea IcfTe than a fixed ftar , now ap-
P^^^th beheld from the Earth ? From thence therefore we
j^^^^ld then judg that felf fame thing to be little, which noTv from
^"^c We cfteem to be immeafurably great.

Great in my judgment, is the folly of thofe who
to h ^^^^ '^^^^ ^^^^ Wodd more proportinal

X2th "^^^^w capacities of their reafon , than to his immcnfe,

X' ^^finite power.
Whi k"" u ^^'^^ that you fay is very true but that upon
fia i , ^^^verfary makes a fcruple , is, to grant that a fixed
r fliould be not onely equal to , but fo much bigger than the
1L ^ 5 when as they both are particular bodies ficuatc within the

K Starry

53t

f^anity of thofe
mens dtfcourfewho
jnd^ the ftarry
fphtre too vafi in
ths Copcrnican
tiypothefs.

* S/>/7/o«c(7/4','Jvhich
is hcrr pur for the

The fpace af-
h^fd to a fixed
fi^^'i umuchieffe
than that of a PU*
ttet.

*A ftar is cal'
led inrefpeEt of the
f pace that environs
it.

The whole ftar-
n.fphere hehdd
from a great 4*-
fiatice might ap»
pear as fmall at
o»t fingle ftar.

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

33^

fiances of th
yltuhur of the
Conclafvns vfty
of interrogation,

» Or Gulph.

Anfrvers to the
iftfgrr oratories of
the faid Amhour.

Ihe t/4uthour
of the Conclttfi",
ons tonfoHnd and
contradt^s him-
felfin hit i»terro'
Rations.

Inter egdtories
pHt to the iyiu'
thour of the Con-
clajionsy by which
the rveakneffe of
hif umAde Aopear,

G. G A L I L ^ u s , his Syflerr.e.

Starry Orb : "-^ And indeed in my opinion this Authour very
pertinently qiieftioneth and asketh : To what end , and
for whofe lake are fuch huge machines made > Were they
produced for the Earth , for an inconfiderable point ? Ana
why fo remote > To the end they might ieem ib very foal'j
and might have no influence at all upon the Earth ^ To
what purpolc is iacii a needleffe monftr. us * immenficy be-
tween them and Saturn ? All thofe affertions fall to the
ground chat are not upheld by probable reafons.
S A L V. 1 conceive by the queftions which this perfon asketii,
that one may c jika , that in cafe the Heavens , the Stars , ^^^^
the quantity of their diftances and magnitudes which he hath
hitherto held , be let alone, (although he never certainly taiicie^
to himfelf any conceivable magnitude thereof ) heperfcSly du'
cerns and comprehends the benefits that flow from thence to the
Earth, which is no longer an inconfiderable thing , nor are they
any longer fo remote as to appear fo very fmall,but big enough
be able to operate 'on the Earth , and that the diftance betwee||
them and ?,attirn is very well proportioned , and that he, foj*^^
thcfe things, hath very probable reafons ^ of which I woulcl g^^
ly have heard fome one : but being that in thefe few wotd^
confounds and contradifts himfelf, it maketh me think that ^
is very poor and ill furniflied with thofe probable reafons ,
that thoie which he calls reafons , are rather fallacies , or dreaiH^
of an over-weening fancy. For I ask of him , whether thefe
leftial bodies truly operate on the Earth, and whether for the
working of thofe efFcfts they were produced of fuch and fucl»
magnitudes , and difpofed at fuch and fuch diftances , or clj^
whether they have nothing at all to do with Terrene mattets-
they have nothing to do with the Earth \ it is a great folly
that arc Earth-born, tooff.r to make our fe Ives arbitrators/^
their magnitudes , and regulators of their local difpofitions , ^
ing that we are altogether ignorant of their whole bufineffe an
concerns , but if he (hall fay that they do operate, and that tW
aredire&ed to this end, he doth affirm the fame thing ^^^^^^
little before he denied , and praiieth that which even ^i^^
condemned, in that he faid, that the Celeftial bodies ^^^^^^-^^
far remote as that they appear very fmall , cannot have an/
fluence at all upon the Earth. But, good Sir, in the Starry^?
pre-eftabliftied at its prefent diftance , and which yoU
knowlcdg to be in your judgment, well proportioned ^^^y
influence upon thefe Terrene bodies , many ftars ^PP^^^ pUc
fn^all , and an hundred times as many more are wholly '^^^^
unto Us (which is an appearing yet leffe than very fi^^\^
therefore it « ticceffary that (contradifting your felf)

A LO Gtl E

111

337

J^ow deny their operation upon the the Earth , or clfe that (ftill

fmall

^^ntradifiing your felf ) you grant that their appearing very
doth not in the leaft lelTen their influence , or elfe that ( and this
ftall be a more fiuccre and modcft conceffion) you acknowledg
and freely confeffe , that our pafling judgment upon their mag-
nitudes and diftances is a vanity , not to fay prefumption or
raftincffe.

Simp. Truth is, I my felf did alfo, in reading this paffage
perceive the nianifeftcontradiaion 5 in faying, that the Stars (if
> one may fo fpeak^ of Coperrhcm appearing fo very fmall, coM
not operate on the Earth, and not perceiving that he had gtatitcd
au influence upon the Earth to thofe of Ptotojuy^ and his feSa-
^ors, which appear not only very fmall, but are, for the moft
part, very invilible.

S A L V. But I proceed to another confideration : What is the
reafon, doth he lay, why the ftars appear fo little ? Is it haply,
'^ecaufe they feem fo to us ? Doth not he know, that this com-
niethfrom the Inflrument that we imploy in beholding them, to
^vj^from our eye > And that this is true, by changing I nftm-^
n^ent, we fliall fee them bigger and bigger, as much as we wfli.
Knd who knows but that to the Earth, which bcholdeth thent
Without eyes, they may not (hew very great, ahd fuch as in reali-
ty they aie? But it*s time thar, omitting thcfe trifles, wc come
to things bf more moment ^ and therefore I having already de-
monftrated thcfe two things : Firft, how far ofF the Firmament
ought to be placed to make, that' the grand Orb eaufeth no grea-
ter difference than tha-t which the Terreftrial Orb occaiidneth in
the remoteneife of the Sun ^ And next, how likewife to make
that a flar of the Firmament appear to us of rhe fame bigneffe,
as now we fee it, it is not necefl'aiy to fuppofc it bigger than thfc
Sun ; I would know whether tyc^ha, or zny of his adherents hath
^ver attempted to find out, by aiVy means, whether any appea-
^^ncebetobedifcovered inthe ftarry Sphere, upon which one
^ay the more refoUitely deny or admit the annual itidtiorl of
Earth.

S A G R. I would anlwjr for them, that there is nor, ndt^irtbt
*ereany need there fliould ^ feeing tharit is C^fem^/i^ himlelf
^hat faith, that no fuch diverfity is there : and they, arg'iimg /r^
W/;/e;;2, admit him the fame ^ atid upon: this i^ffumption they
f^tnonftrate the improbability that fdllciwetli thereupon, name-
tW it would be neceffary to- make ite Sphere fo imrtienfe,
that a fixed ftar, to appear unto us as greifa^ it now feems, ought
of neceflity to be of fo immenfe a magnitu^, asr tftat it would
m exceed the bigneffe of the whdle grand Orb, a thiuj^ AVh^th riot-
■ ^ithftanding, as they fay, is altogether incredible.

Th4t remote ^
jtUs ofpenre fo
(mull^ ftf the defei^
of the r/r , ds <jf
dtfmnfirAtedo

Tycho net hk
followers ever 4f-
tempted to fee whe*-
ther there are anf
dfpegrMnces ut the
Firmament for of.
agAinfl the Mn^M
motiefit

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

338 G. •Galii^us, Syjlcme.

, S A t V. I am of the fame judgmenta and verily believe that
they argue contra homineMy ftudying more to defend another
inan,than defiring to come to the knowledge of the truth. Ani
perhlfsTh^vTno] ^ ^"'^ believe, that none of them ever applied thcmfelveb

perhaps, have not * ~ , I ^""r a^^iiLu uiww*...^-

known xvhMt ap- ^laKe any lucfa obiervation, but I am alfo Uncertain 5 whether
^'u^^oZt'Z ^f^J^^™ do J^now what alteration the Earths annual motion
nulmotTonoftht Ought to produce in the fixed ftars, in cafe t)ie ftarry Sphere were
E4rth. not fo far diftant, as that in them the faid diverfity, by reafon of

its minuity dif-appeareth , for thtir furceafing that inquifition?
and referring thcmfelves to the meer affertion of Copernicus^
may very well ferve to convift a man, but not to acquit him of
Copcrnicus««. ^^e faft ; For its poffible that fuch a diverfity may be, and yef
Atrfiood, not feme not havc bccn fought for j or that either by reafon of its miaui'
%^rJZntr ^^'^ ^^"^^^ ^^^^ Inftruments it was not difcovered by Co-

fernicHs ^ for though it were fo, this would not be the firft things
that he either for want of Inftruments, or for fome other dcfe^
hath not known , and yet he proceeding upon other folid anJ
rational conjefturcs, affirmeth that, which the things by him n^^^
difcovered do feem to contradid : for, as hath been faid already
without the Tclefcope, neither could Mars be difcerned to in'
crcafe 60. times *, nor Venus ^o. more in that than in thispofi"'
on 5 yea, their differences appear much leffe than really they are-
and yet nevertheleffe it is certainly difcovered at length, that
thofc mutations arc the fame, to an hajj: that the Copernican S/'
therWgle 4- ^^"^e required. Nowit would be very well, if with the greateft
l^infl the annual accuratcncffc poffible one (hould enquire whether fuch a muta-
Z::dZ:X ^^^^ ^\ ^^g^^ ^5 difcoverabk in the fixed ftars, fuppofing the
tion^f the Pole, annual motion ot the Earth, would be obferved really and in
cfFeft, a thing which I verily believe hath never as yet been don^
by any , done, faid I ? no, nor haply (as I faid before) by ma'^X
well underftood how it ought to be done. Nor fpcak 1 this at
randomc , for I have heretofore feen a certain Manulcript
one of thefe Anti^Copernicans^yNliich faid, that there would oc-
ceffarily follow, in cafe that opinion were true, a continual ti'
fing and falling of the Pole from fix moneths to fix monetbs, ac-
cording as the Earth in fuch a time, by fuch a fpace as is the diaj
xpeter of the grand Orb,retireth one while towards the North,aii^
another while towards the South j and yet it feemed to him reai^^'
nable, yea neceffary, that we, following the Earth , when we vv^re
towards t/ie.North (hould have the Pole more elevated tha?
^;. we are to\yards the South. In this very error did one fall that
* thriftopliorlis Ptherwife a very skilful Mathematician, & a follower o(Coperni^'
Kothmannus. as tjyrfe^. Tela tcth in his ^Progymnafma.pag. 684,which faid,that he
M obferved the Polar altitude to vary, and to differ in Summed
trom what it is in Winter : and becaufe Tycfc^, denieth the

DiAlogueHI;

of the caufe> biit findeth no fault with the method of it j that
is, denicth that there is any mutation to be feen in the altitude of
tfie Pole, but doth not blame the inquifition, for not being adap-
ted to the finding of what is fought, he thereby fliewcth, that he
alfo efteeemcd the Polar altitude varied, or not varied every fix
Wionethsjto be a good teftimony to difprovc or inferre the annual
motion of the Earth.

Simp. In truth, Sal^iatHS^my opinion alfo tells me^ that the
f^me muft neceffarily enfue : for I do not think that you will de-
^yme, but that if we walk only 60. miles towards the North,
the Pole will rile unto us a degree higher, and that if we move
60. miles- farther Northwards, the Pole will be elevated to us a
degree more, &c. Now if the approaching or receding 60, miles
onely^ make fo notable a change in the Polar altitudes, what
J^lteration would follow , if the Earth and we with it, fhould

tranfported, I will not fay 60. miles, but 60. thoufand miles
^hatway.

Sax V. Ic would follow (if it ftiould proceed in the fame
proportion J) that the Pole fliall be elevated a thoufand degrees.
See^ Sfwplicif^, what a long rooted opinion can do. Yea , by
^eafon you have fixed it in your mind for fo many yeare, that it
is Heaven , that revolveth in twenty four hours , and not the
Earth, and that confequently the Poles of that Revolution are in
Heaven, and not in the Terreftrial Globe, cannot now, in an
tours time fliake off this habituated conce,ipt, and take up the
contrary, fancying to ydur felf, that the Earth is that which mo-
Vcth, only for fo long time as may fufficc to conceive of what
>^ould follow, thereupon fliould that lye be a truth. If the Earth
^tfftplicitis^ be that which moveth *m its felf in twenty four hours,
it arc the Poles, in it is the Axis, in it is the Equinofiial, that
^3 Ae grand Circle, dcfcribed by the point, cquidiftant from the
**oles, in it :lre the infinite Parallels bigger and lefTcr defcribed by
^'^e points of the fuperficies more and leffe diftant from P^^l^s,
ij^ it are all thefc things, and not in the ftarry Sphere , which, as
'^.^'"g immoveable, wants them all, . and can only by the imagina-
J.*''^ be conc-eived to be therein, prolonging the Axis of the Eart^
f^r, till that determinina it fliall mark out two points placed
'^ght over our Poles, and the plane of the Equinoftial being. ex-
^^«d^d, it (hall defcribe in Heaven a circle like it felf. Now it the
5'^^ Axis, the true Poles, the true Equinoftial , do not change
Earth fo long as you continue in the fame place of the
f^^^f^' and though the Earth be tranfported, Y^^^^ P^^^^^^
y^t you (hall not change your habitude either to the Poles, or to
^he circles , or to any other. Earthly thing and this becauie, that
^hat tranfpofition K.in^ rnmmonto you and. to all Terreftrial

tion beine common to yc
^ V V

things;

^)9

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

94 c

G. G A LI L ^ u s, bit Syfieme:

Afotion where
it U common^ is as
if it never wire.

An example fit-
ted to prove that
the altitude of the
Pole ottght not to
vary by means of
the Earths annual
motion.

* Corfiay the bank
or bench on whxh
fiaves lie in a Gal-

^ and that motion where it is common,
were^ and as you change not habitude to the Terreftrial Poles
(habitude 1 fay, whether that they rile , or defcend) fo neither
fliall yba change pofition to the Poles imagined in Heaven j
way es provided rhat by Ccleftial Poles we undcrftand (as hath
been already defined) thofe two points that come to be marked
out by the prolongation of the Terreftrial Axis unto that length-
Tis t'rlie thofe points in Heaven do change, when the Earths tran-
fportment is made after fuch a maniicr) that its Axis come th to
paffe by other aild other points of the immoveable Celeftial
Sphete s btit our habitude thereunto changeth not, fo as that the
fccond fhould be more elevated to us than thefirft. If any
will have one of the points of the Firmament, which do anfwer
to the Poles of the Earth to afccnd , and the other to defcei^J?
he miih Walk along the Earth -towards the one, receding from tb^
oeher I for the trarnfpoitment of the Earth, and with it us ou^
felves, (as I told you before) operates nothing at all.

Skofe* Permit me , Ibefeech you Salviatm ^ tomakethis^
little 'riWD^e clear by an example , which although grolTc, i^^'
commodated to this purpofe. Suppofe your felf, ^impltci^^^^
be aboard a Ship , and that Handing in the Poope, orHin-^^*
you h¥V^ direfted a Quadrant , orfome other Allronomical
ftrumeilti towards t-he top of the Top-gallant-Maft , as if
wouM take its height , which fappofe it were 'v. gr. 40. degf^^^'
the r^^Vs ho doubt, bi^ that if you walk along the Hatches t<J-
Wardithe Maft ^5. or 30. paces ^ and then again direfi^h^^^^
Inftru^nt to the fame Top-Gallant -Top. Y ou fliall 6 tid. its ele-
vation tb be greater , sipd to be encreafed gr. i o. degrees but
if infiead of walking thofe 25. or 30. paces towards theMaft'
you fta'rid ftill at the Sterne , and make the whole Ship to ii'^'^^
thithe^rwards 5 do you believe that by reafon of the 25. o^3^'
padEfs<^]^hiit it badpaft , the elevation of the Top-Gallant'^^
wotrld rtlew I o. degrees encreafed ?

S I M p. I believe and know that it would not gain anh^^
bre«tdi?h in the pa(fing of 30. paces , nor ofathoufand,non^>^^^
an hundred thoufand miles ^ but yet I believe withal that loo
tng through the fights at the Top and Top-Gallant , if ^ ^^^y
fimlafixed Star that was in the fame elevation, I believe l^^Q
that, holding ftill the Quadrant, after I had failed t^^^^jf^fj^jd
ftar ^0. ttiiles , the eye would meet with the top of ^'^^
Maft^ as before , but not with the ftar , which would be
ted to? me one degree. ^

S A G t^. Then you do not think that the fight would fell
that point of the Starry Sphere , that anfwereth to the direct^
of ^^^Tfep^GalkritTop? ■ ,

as if it never

I A LOG UE.

III.

341

bcj

Simp. No: For the point would be changed , and would be
neath the ftar firft obferved.
S A G R. Y^ou are in the right. Now like as that which in this
example anlwereth to the elevation of the Top-Gallant-Top, is
Jiot the ftar , but the point of the Firmament that lyeth in a right
line with the eye, and the faid top of the Maft , fo in the cafe
exemplified , that which in the Firmament anfwers to the Pole
the Earth, is not a ftar, or other fixed thing in the Firma-
"\^"t > but is that point in which the Axis of the Earth continu-
?^ ftrcight out, till it comcth thither doth determine , which point
^^i^ot fixed, but obeyeth the mutations that the Pole of the
Eaith dotti make. And therefore Tycho , or who ever clfe that

did
fami
difFc

✓ -. .- upon the annU"^^

^'ledg this obicftibn , ought to have faid that upon that

^. > . , t ^ ^ Emh^Alteratiok

may enfue JM.
fome fixed ftnTf
m in the Tolt,

^motion of the Earth, were it true, one itiighc obferve fome
^UTerence in the elevation and depreflion (not of the Pole, but)
^uome fixed ftar toward that part which anfwereth to our Pole.

S i m p. 1 already very well underftand the miftake by them
committed o "but yet therefore (which to me fe^ms very^reat) of
the argii0|ei^t brought on the contraLy is not leflened , fuppo-
^^"g relatioi^ to be had to the variation of the ftars , and not of
^he Pole for if the moving of the Ship but 60, miles , make a
fixed ftar rife to me one degree , fhall I not find alike , yea and
Very much greater mutation , if the'Ship fliould fail towards the
Vid ftar, for fo much fpace as is tHc , Diameter of the Grand
Orb , which you affirm to be double the diftahce that is between
theEarth and Sun?

Sag r. Herein SmpUcim , there is another fallacy ^ which,
truth IS, ypu underftand , but do not upon the Tudden think of
h"^V ' bring it to your remembrance : Tell

e therefore ^ if when after you have direSed the Quadrant to
^hxed ftar:

and found g» its elevation to be 40. degrees,
(hould without ftirring from the place, incline the fide of
^ Quadrant , fo as that the ftar might remain elevated above
"^t direftion 5 would you thereupon fay that tbc ftar had acqui-

greater elevation >
^ I M p. Certainly no : For the mutation was made iiijtheln-
: V^^^ent ^nd not in the Obferver , that did change place j mo-
^?«g towards the fame.
^ ^ But if you iail or walk along the furface of the Terre-

The eqHhfike of
thofe rpho believe
that in the dnnual
motion ^reat mtt-
tations are to he
mtide about the
elevation of a fix*
edjtary is confn*
ted.

faid

Qpadr

ft * 1 J - *j

^trial Globe , wilf you fay that there is no alteration inade in the
but that the fame ele^
wens , fo long as you ;
K — * at its firft conftitution i
iho H^" ^**ve me leave to think of it. I would fay without
re ado, that it would not retain the fame, in regard tliepro-

fireffe

f n y-^ant , but that the fame elevation is ftill retained in re-
bn 1 • Heavens , fo long as you your felf do not incline it,
tietitftand . r n conftitution?

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

34^

G; G A L I L A u s , M Sjfime.
'greffe I make is notinplauo but about the circumference of the
Terreftrial Globe 5 which at every ftcp changeth inclination m
refpefl to Heaven , and confequently maketh the fame change
in the Inftrument which is ereficd upon the fame. *

S A G R. You fay very well : And you know withal , that by
how niuch the bigger that circle (hall be upon which you move,
fo many more miles you are to walk , to make the faid ftar to
rife that fanie degree higher ^ and that finally if the motion to-
wards the ftar fliould be in a right line , you ought to move yet
farther 5 than if it were about the circumference of iiever io
great a circle ?

The right line, Sal v. t'rue : For in fhort the circumference of an infift^^
i»4 ctrcumfcre^c^! circle, and a right line are the fame thing.
fu%\Tttl^f^mc Sagr. But this I do not underftand, nor as I believe, doth
thi»tg. SimpliciHS apprehend the fame , and it muft needs be conccale

from Us under fome miftery , for we know that Sali'iatus neV^^
fpeaks at random , nor propofeth any Paradox, which doth t^^^
break forth into fome conceit, not trivial in the leaft. Thercf*^^^
in due time and place I will put you in mind to dcmonftrate tbi^^
that the right line is the fame with the circumference of an'^^^'
nite circle , but at prefcnt I am unwilling that we fliould
rupt the difcourfe in hand. Returning then to the cafe , ^ P^^j
pole to the confideration of SiffipUcius , how the acceflion an
receflionthat the Earth makes from the faid fixed ftar whicn
neer the Pole can be made as it were by a right line , for fueh^^
the Diameter of the Grand Orb , fo that the attempting to f^'
gulate the elevation and depreffion of the Polar ftar by the mO'
tion along the faid Diameter , as if it were by the motion abot^^
the little circle of the Earth / is a great argument of but lit^'^
judgment.

Simp. But vve Continue ftill unfatisfied, in regard tb^^-^
faid fmall mutation that fliould be therein , would not be dii^^^
ned 5 and if this be null , then muft the annual motion at>
the Grand Orb afcribed to the Earth, be nnll alfo. j
S A G R. Here now I give Sal^iatm leave to go on, ^'^^^L
believe will not overpaffe the elevation and depreffion ^ |^
Polar ftar or any other of thofe that arc fixed as ///ifl, altho<
not difcovered by any one, and affirmed by Copernicus ^^^^\\is
to be , I will not fay null , but unobferVable by reafon *
minuity. . /V. . , . hat

S A L V. I hive a!r(e<i(ly faid above, that I do not
XlmZlliZl!^ any one did ever fet himfelf to obfcrve, whether in different tiij^^^
<» tlitt fltrhirtto of the year there is any mutation to be feen in the fixed ftar*' ' i
U aicoverci, bj Way have a dependance on the annual motion of the Earth) ^
7,7 Jjn c/Z ^^^^^ Withal, that I doubted leaft haply fome might never b»J^

I ALOGUE. I It

^y^deiftood what thofe mutations are , and amongll what ftars
^hcy flioiild be difccrned ; therefore it would be neccffary that
in the next place narrowly examine this particular. My ha-
ving onely found written in general terms that the annual moti-
on of the Earth about the Grand Orb , ought not to be admit-
5 becaufc it is not probable but that by means of the fame
Would be difcoverd fome apparent mutation in the fixed
l^arsjand not hearing fay what thole apparent mutations ought to
in particular , and in what ftars ^ maketh me very rcafonably
^^"^ft ^hat they who rely upon that general pofition , have not
the 5^ p ^ ' poflibly endeavoured to underftand j how

are ?• mutations goeth , nor what things thofe

which they fay ought to be feen. And to this judgment I aril
^rather induced , knowing that the annual motion afcribed
^y^^opcrnicm to the Earth , if it fliould appear fenfible in the
^ ^^fy Sphere , is not to make apparent mutations equal in re-
,P^« to all the ftars , but thofe appearances ought to be nlade
ji^loine greater , in others leffer, and in others yet leffer ; and
^**^V 5 in others abfolutely nothing at all , by reafon of the
^^ft magnitude that the circle of this annual motion is fuppofed
to be of. As for the mutations that fiiould b feen , they are of
two kinds , one is the faid ftars changing apparent magnitude^,
and the other their variation of altitudes in the Meridian. Upon
Which neceffarily followcth the mutation of rifings and fcttings
^nd of their diftances from the Zenith, &c, '
S A G R. Methinks I fee preparing for me fuch a skean of theft
them f"'' ^ "^'^ " '""^y never be my task to dif-intanglc
times Vk ?'''!^^^^'' ""5^ infirmity to SdhiatHs, \ have fome^
it \ , "g^t thereon , but could never find the * Lay-band of
^5 and 1 ipeak not fo much of this which pertains to the fixed
5 as of another more terrible labour which you bring to my
^embrance by maintaining thefe Meridian Altitudes^ Ortive
^^titudcs and diftances from the VertcK, &c. And that which
^^^leth my brains, arifeth from what 1 am m^w about to tell
the 's ^^^^'^^^^ fuppofeth the Starry- Sphere immoveable, and
ni"^ centre thereof immoveable al fa Therefore eve -

fix ^i^^" which feemeth unto us to be made in the Sun or in
^Ut ^^^^^ muftof necefllty befall the Earth and be bus.
arch^ f^^^^^^^^^*^ anddeclineth in our Meridian by a very great
greatet ^^^P^ 47- ^^egrees , and by arches yet greater and
horizon ^^^^^^^'ts Ortive and Decidual Latitudeis in the oblique
^otablv^ ^^whow can the Earth ever incline a!id elevate fb
little 1 and nothing at all to the fixed ftars , or fo

WneveV^ be perceived > This is that knot which
^^^r get thorow my ' Loom-Combe and if you fltaH.

datie

345

t^firoHomers ib^-
vixg omitted to in-
fiance what- alte»
rations thofe are
that may he deri'
ved from the an*
Kual motion of the
Earth , do thereby
teflife that thej
never rightly
der flood the fame.

The mnt^tiont
of the fixed fi»f
ought to be in fome
greater ^ others
lejfer^andtn others
nothing at aH.

* Bandola that
end of a 9kccQ
wherewith houfe-
wives faftcn cl?eir
hankes of yarn,
thread or (Ilk.

the grand iif'
ficulty tn Coper-
nicus hit VoSrine^
*t that which cok^
cerm the Pheno-
mena of the Suit
and fixed fars.

* Pettine, ic ^
the flay inaWea-
vets. Loom , that
pcrmitcf ch no knoc
or fnaric to paflc
ic , called by thctrt
th^ Combfiof th|
Loom-

d by courtesy of the Royal Library, Copenhage

544

Ariftotles drgu-
went againjt the
4nci0Hts^i»ho hild
that the Earth
-peas A TUnet.

The atihkdfmd-
t 'ton made hj the
centre of the Earth
under the_ Eclip^
ticl^ and t};e dmr*
rial moiton f».tde
ij the Earth ahm
its own centre.

The axis jjf she
Earth contimtth
alwajes par^It^J to
itfelf. anddefcri--
heth a CjUndrai'
cal fHperffieSyt^"
dining to \hc

G. G A L I L ^ II s 3 his Sypeme.

untie it 5 I fliall hold you for more than an Alexaudcr.

S A L V. Thcle are Icruples worthy of the ingenuity of Sagn-
dm ^ and this doubt is fo intricate, that even Copernicus himfeli
almoft delpaired of being able to explain the fame , fo as to
render it intelligible , which we fee as well by his own confeffion
of its obfcurity 5 as alio by his, at two feveral timcsj taking two
different wayes to make it out. And, I ingenuoufly contcife that
I underftood not his explanation, till fuch time as another me-
thod more plain and manifeft, had rendred it intelligible ? ^nd
yet neither was that done without a long and laborious appl'^^'
tion of my thoughts to the fame.

Sim f. Artjiotle faw the fame fcruple , and makes ufe there-
of to oppole certain of the Ancients , who held that the Earth
was a Planet i againftwhom he argueth , that if ic werefo,
would follow that it alfo, as the reft of the Planets , fliould have ^
plui-ality of motions , from whence would follow thefe variati'
ons in the rilings and fettings of the fixed ftars , and likewife'^
the Meridian Altitudes. And in regard that he propoundeth the
difficulty 5 and doth not anfwerit, It muft needs be , if nofii^'
pollible 5 at leaft very difficult to be refolved.

Salv. The ftreCTe and ftrengthof the knot rendcretb
folution thereof more commendable and admirable j but I ^
not promife you the fame at this thne , and pray you to difpeJ**
with me therein till too morrow , and for the prcient we will
confidering and explaining thofe mutations and differences th^^
by means of the annual motion ought to be difcerned in the fijC'
ed ftars , like as even now we faid , for the explication whereof
certain preparatory points offer themfelves , which may facil^'
tate the anfwer to the grand ob)eSton. Now reaffuming ^*!^
two motions alcribed to the Earth (two I fay , fdr the ^^^^^^
no motion, as in its place I Ivilljdeclare) that is the annual
diurnal , the firft is to be underftood to be made by the centr^^
the Earth in or about the eircumferenee of the grand Orb,
is of a very gre^t circle defcribedin the plain of the fixed ^
immutable Ecliptick \ the other, namely the diurnal , is
by theGjobe of thi* Earth ia itfelf aboiat its own centre '
own Axis, not trcia, but iiiclined to the Plane of thcE^^'P^^L'
with the incUnation of 35. degrees and an half, or th^r^^^^^j^^^
the which incliijia^iion is ttiaimained all the year about ,
which ought efpeeially to be obfervcd , is al wayes ^^^^^^^r
wa^rds the fame point of HeaVien : *in fo much that the
diurnal motion doth alwayee remain parallel to it felf 5

% imagine that fame Axis to be continued out until it
thQ fixe4 ftars .^whilft.the centre of the Earth is ^ncircling^ ^
wh<^le llGhptid^^ ^ year V the foid Axis defcribcth the i^T^^

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

I A LOG U E

111

34^

ficies of an oblique Cylinder ^ \vhidr hath for one of itsbafes

fhc iaid

id for the other a like circle

imagma-

lily dcicribcd by its. extremity , or^ (if you will) Pole , amongft
^he fixed ftai s. And tliis fame cylinder is oblique to the Plane of
theEcliptick , according to the inclination of the Axis that de-
Icribcth it, which we have faid to be 23 degrees and an half,
the which continuing perpetually the fame (favc onely, that in
i^any thoiitandsof years it maketh fome very fmall mutation,
which nothing importeth in our prefent bufineffe) caufeth that
the Terreftiial Globe doth never more incline or elevate , but
ftill confcrveth the fame ftatc without mutation. From whence
enlucth , that as to what pertaineth to the mutations to be ob-
^^rvcd in the fixed ftars dependant on the fole annual motion?
^jie fame (hall happen to any point whatfoever of the Earths
^Mrface, as befalleth unto the centre of the Earth it felf , and
therefore in the prefent explanations we will make ufe of the
^<^nt;re , as if, j|; were any whatfoever point of the fuperficies.
A.nd foi a mofC facile underftanding of the whole let us dcfign
^he fame in lineal figures = And firft of all let us defcribe in the
PJane of the Ecliptick the circle A N B O [i/i Fig. 7.] and let
iinderftand the points A and B , to be the extreams towards
the North and South 5 that is, the beginning of [(?r entrance into']
Cancer or Capricorn •i, and let Us prolong the Diameter A B , in*
ietcrminately by D and C towards the Starry Sphere. 1 fay
^tow in the firft place , that none of the fixed ftars placed in the
Ecliptick , (hall ever vary elevation , by reafon of any whatfo*
ever mutation made by the Earth along the faid Plane of the
^-cliptick , but fh^U alwayes appear in the fame fuperficies , al-
though the Earth (hall approach and recede as great a fpace as is
that of the diameter of the Grand Orb , as may plainly be
*?enin the faid figure. For whether the Earth be in the point
^ or in B , the ftar C alwayes appeareth in the fame line A B C5
although the diftance B C , be leife than AC, by the whol^
^iameter A B. The mpft therefore that cati be d^fcovered in the
C , and in any other placed in the Ecliptick,. is the aug-
"^^^ted or diminiflied apparent magnitude , by reafon of the ap-
Pfoxiruation or receflion of the Earth.

^aqr. Stay a while I pray you, for I meet with a certain
J^^^Ple , which much troublcth me ^ and it is this.? That the ftar
V may be feen by the fame line A B C , a* wel when the ^Earth
J' "^^> as when it is in B, I underftand very well, asalfpfot-
thcrmor^ 1 apprehend that the fame would happen in all the
pomts of the line A B , fo long as the Earth (houjd pafTe frpn^
[oB by the faid line- but it pafling thither, as is, to be fupppfecj,
the arch AN B, it is manifcft that when it (halite ii^thc

X X point

The Orh of the
Earth never ineli"
aeth , hm it im-
mtttaifljthefame.

The fixed fiarS
placed in the £-
cliptick. never ele*,
VMte nor defcendt
on Account of thfi
4HnuMi motion^ hut
yet approMfh 4nA
recede^

OhjeStions

the Earths ^nmul

motion takftfrotit

the fixed ' ^art

pldced is the t',

tliptiaV^

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

34^

tj; G

A L I L AUS

ume.

* Or will prove
of good alloy.

point N

)ther

thofc two A and B , the faid

ftar ftiall
So that,
apparent
this cafe,
freedom

except

noloivger be obfcrved in the line A Bj but in others,
if the appearing under feveral lines ought to canU
mutations ^ fome difference muft needs appear in
Nay more , I will fpeak it with that Philoibphic^'
which ought to be allowed among ft Philorophick
friends 5 methinks that you , contradifling yourfelf, deny that
now 5 which but even now to our admiration, you proved to
really true , and cbniiderable ^ 1 mean that which happcneth in
thePlincts, and particularly in the three fuperiour ones, th^^
being conftantly in the Ecliptick , or very near unto it , do n^f
onely fliew themfelves one while near unto us , and anotliff
w hile remote , but fo deformed in their regular motions , that
they feem fometimes immoveable , and fometimes many dc
grces retrograde ^ and all upon no other occalion than the air
nual itibtion of the Earth.

S A L V. Though by a thoufand accidents I hj^^e been hereto-
fore affuted of the wittineffeof Sagredm , yetMiad adeflr^'')
this one experiment more to afcertain me of what I may cxp^^
froni his ingenuity , and all ^hisfor my own intereft , {or 'm ^^^^
my Pi-bpofitioM ftand but proof againft the hammer and t^^'
tiace of his judgiitent , 1 fliall be confident that they will abio^
the * teft of all Tbuch-ft6nes. I fay therefore that I had f^^'
]^ofcly diffcttibli^d this objeflion , but yet not with any intentt^
a^tdye^you^, and to put any falfhood upon you , as it tnigbt
*aveiiiippetiedif the objeaionby me difguifed , and by you
vef-leokt , ha^ been the fame in effeft as it feemed to be in
f^zn^tt ^ that is, really valid and conclufivc ^ but it is not^^'
ii^ay I father fufpeft that to try me , you makj as if you did
fee ifris niillity. But I will herein be too hard for you , and f^^j^^
fiWft ybur tbngoe;, that which you would fo artificially conc^^' '
<aA^t4iei'tfore ttlltne, what that thing fhould be , whereby
^iriWrtt t^^krtbw Ae ftation ^and retrogradation of the planets?
mifeh b a^tA frbm the annual motion , aud which is fo g^^^!'
that dlcaft fortifc foot-ftepsdf fuch anefFeft ought toapp^^*^
tbc fttfrs of the Ecliptick >

S A G R. This demand of yours containeth two quefti^^i'^' ^
u4nG}iitis ^aeaeff&ty that I make reply ^ the firft relates jJ^J
ftWputatioh whit6 you Jay upon me of a Diffembler ', L
Cdh^fcrheth that which may appear m the ftars, ci^c. ^ V )
*ftS 'l ^ill Tay with your permiffion , that it is not true , tbj.

di{fcmbl6d hiy knowing the nullity of that ob)cfti<^^^'
^'affureyoa of the fame , I now tell you that I very wcH
ftanditfe^ nullity thereof. • ,
b A L V. Etit Vet I do hbt utiderftand how it can be, that f

i fpak^^

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

I ALOGUE.

IIL

I^P^'ve not friendly , when you Hxid you did not know that fame

fallacy which you now confeffc that you know very well.

Sagr. The very confeflion of knowing it may alTure yon
^"it I did not diflemble , when itaid that I did not undcrftand iti

Or if I had had a mind, and would diffemble, who could hin-
me from continuing in the fame fiiilulation , and denying ftill
^^^^ 1 undcrftand the fallacy ? I fay therefore that I underftood
the lame, at that time , but that I do now at this prefent ap-
Pi*^iiend it , for that you haVe prompted my intelleft , firft by

^ me rcfolutcly that it is mill ^ and then by beginning to
mi^h "^c fo at large \^hat thing that might be , whereby t
net^ ^ ^^^^ to know the ftation and retrogradation of the Pla-
fL bccaufe this is known by comparing them with the fix-
^. ^^^s, in relation to which, they are feen to vary their nid-
^^"s, one while towards the Weft , and another towards the
jg ' i^i^d fomctimcs to abide immoveable, and becaufe there

s not any thing above the Starry Sphere, immenfely more remote
^ Us ^ and vilible unto us , vVhcrewith We may compare our
^^^^ ftars^ therefore we cannot difcover in the fixed jftarsan^
loot-ftcps of what appearcth tons in the Planets. This I believe

the fubftance of that which you would force from me.
S A L V. It is fo , with the addition moreover of your admi-
rable ingenuity ^ and if with half a word I did open your eyes,
you by the like have remembred rtie that it is not altogether im-
Poffible, but that fometimeor other fomcthing obfcrvable may

etound amongft the fixed ftars , by which it may be gathered

leffe'th' ^""^^^^ converfion refides , foas that they alfo no

bear wT ^ r'"""^^' ^^""^ "^^y ^PP^^^* judgment to

th* I , "^"^ ^'^^^ motion, in favour of the Earth i for 1 do not
UK that the ftas arc fpread in a Ipherical fuperficies equally re-
^te from a common centre , but hold, that their diftances frorri
^^^refo

347

The fistim^di*
reUion and retrc'
gradation of thi
PUnets u kfi<^f>^
fn reUtioM to th
fixed fiars.

Indice in
the fix^d ftars likf
to that which it
[ten in the FU-
nets , u At7 ar£M-f
mem of the Earth f
Mnnftal motion^

j,^^ote as Others fo that if with the Telefcope one ihould ob
the^^/ ^^^y fniall ftar neer to one of the bigger , and which
fenfU was very exceeding high , it might happen^ that fomc
to h "^^^^^ion might fall out between them , correfponderit
fp , the fuperiour Planets. And fd triuch (hall ferve to have
Let touching the ftars placed in the Ecliptick.

andle ^^^^ ^^^^ ^^^^ ' ^^^^^^ ^^^^^ Ecliptick,
ti\ the^pf^PP^^^ a great circle ereft upon [/. e. at rigkt angles
tie th ^ . the* fame; and let it , for example, beacir-

^ndl t ^^^^^y Sphere anfvvers to the Solftitial feolure ,

various , thslt fome of them mly be twice and thrice as

VithalaM^'^^'^EH [///f/g.8.] which (hall happen to be
\ u'l ' ^^^^ ^^'^ ^^^^ ^ withdut the Eclip-
v^i^iGh lee be E. Now this ftar will indeed vary its elevati-
X X 3 on

The fixed fim
i^ithout tbeEclip*
^'^k. elevate dnd
defcend mtre er
l<fe^ accordinfi t»
their difiance from
the [did Ecttf tick.

*i. f.of chcjE-
clipcick* ^

G; G A L 1 L ^ u s ^ his Sjfl(me.

on Upon the Earths motion j for from the Earth in A tt (liallbe
feen according to the ray A E , with the elevation of the angk
E A C 7 but from the Earth placed in 6 , it (hall be fccn ac-
cording to the ray B E , with Ibe elevation of the angle E B C,
bigger than the other E AC , that being extern , and this in-
tern and oppofite in the triangle E A B, the diflance therefore
of the ftar E from the Ecliptick , fliall appear changed h and
likewife its altitude in the Meridian fliall become greater in the
pofition B , than in the place A j according as the angle E B C
exceeds the angle E A C 5 which exceflfe is the quantity of ^he
angle A E B : For in the triangle E A B , the fide A B being
continued co C , the exteriour angle E B C (as being equal to
the two intcriour and oppofite E and A) exceedeththe faidaP'
gle A, by the quantity of the angle £. And if we-fliould take
another ftar in the lame Meridian , more remote from the Ecli-
ptick , as for inftance the ftar H , the diverfity in it fliall he
greater by being obferved from the two ftations A and B , accor-
ding as the angle A H B is greater than the other £ 3 which an-
gle fliall encreafe continually according as the obferved ftar ft^^'
be farther and farther from the Ecliptick , till that at la^^
greateft mutation will appear in that ftar that fliould be placed m
' the very-Pole of the Ecliptick. As for a full underftanding there-
of we thus dcmonftrate. Suppo{e the diameter of the Cran<*
Orb to be A B , whofe centre [^inthe f^me Figure'] isG,
let it be fuppofed to be continued out as far a? the Starry SphefC
in the points D and C, and from the centre G let there be erefteJ
the Axis of the Ecliptick G F , prolonged till it arrive at the fai^J
Sphere , in which a Meridian D F C is fuppofed to be defcrib^^*^
that fliall be perpendicular to the Plane of the Ecliptick ? ^^^^
in the arch F C any points H and £, are imagined to be takeii>
as places of fixed ftars : Let the lines FA, F B, AH?
H B3 A £.5 G £5 B be conjoyned. And let the' angle oi^^^'
ferencc , or, if you will, the Parallax of the ftar placed in th^
Pole F , be A F B , and let that of the ftar placed in H , be the
angle AH B , and let that of the ftar in£ , be the angl^
A £ B. I fay, that the angle of difference of the Polar fl:ar F,
the greateft , and that of the reft , thofe that are nearer to
greateft are bigger than the more remote that is to fay, th;*^
angle F is bigger than the angle H, and this bigger than the ^^^g^^
E. Now about the triangle FAB, let us fuppofe a circle to be de-
fcribed.And bccaufe the angle F is acute, (by reafon that itsh^'^
AB is leffe than the diameter DC, of the femicirde D F C)it<^^'^
placed in the greater portion of the circumfcribed circle c\Jt
Mft^ b^fe A B. And becaufc the faid A B is divided in the
lindlt, and at right angles by E C, the centre of the circumfcri'

bed

Dialogue Uli

^^d circle fhall be in the line F G, which let be the point I i and
^ecauie that of Inch lines as arc drawn from the point G, which

not the centre, unto the circumference of the circumfcribed
circle, the biggeft is that which paffeth by the centre , G V (hall
be bigger than any other that is drawn from the point G , to the
^^^^iimfcrcnce of the faid circle and therefore that circumfe-
rence will cut the line G H (which is equal to the line G F) and
putting GH, itwillalfo cut AH. Let it cut it in and con-
Joyn the Vme L B. Thefc tWo angles, therefore, A F B and ALB
fliall be equal, as being in the fame portion of the circk cir-
cmnfcribcd. But ALB external, i^ bigger than the internal H 5
^nctcforc the angle F is bigger than the angle H. And by the
*3nie me^od we itiight: dcmonflrate the angle H to be bigger
than the angle E, becaufe that of the circle defcribed about the
tnaivgle A H B, the centre is in the perpendicular G F, to which
*e line G H is nearer than the line G E, and therefore the cir-
cumtercnce of it cutteth G E, and alfo A E, whereupon the pro-
pofition is manifcft. We will conclude from hence, that the dif-
^^i'encc of appearance, (which with the proper term of art, wc
Wight call tlic Parallax of the fixed ftars) is greater, or lefTe, ac-
cording a§ the Stars obfervcd are more or lefFc adjacent to the
Pole of the Eclipcick, fo that, in conclufion of thofe Scars that
are in the Echptick it felf, the faid divevfity is reduced to nothing,
la the next place, as to the Earths acceffion by that motion to,

rccefiion ftoiti the Stars, it appeareth to, and recedeth from
thofe that are in the Ecliptick, the quantity of the whole diamie-

Qf the grand Orb, as we did fee even now , but that acceflion

tcceffion to, of from flie ftars about the Pole of the Ecliptick,
IS almoft nothing j aild in going to and from others, this diffe-
rence groweth greater, according as they are necrer to the Eclip-
^^ck. We may, in the third place, know, that the faid difference

Afpe^ groweth greater or leffer, according as the Star obfcr-
fhall be ncercr to u^? or farther from us. For if we draw a-
Mother Meridian, lefTe diftant from the Earth *, as for example,
this Dpi Fig, 7.] a Star placed in F, and fcen by the fame
ray A F E, the Earth being in A, would, in cafe it fliould be ob-
erved from the Eartt in B, appear according to the rayBF, and
^ould make the angle of difference , namely , B F A , bigger
^^an the former A E B, being the exteriour angle of the trian-
gleBpE,

V ^"^rr/" g^^^^ delight, and alfo benefit have I heard

Iv^ ^ ^ A ^^"^ ' ^'^^^ ^ may be certain, whether I have right-
y unucrltcodthe feme, I (hall give you the fummeof the Con-
^, "^^^^^ ^ Words. As I take it, you have explained to us
^i^crent appearances, thit by means of the Earths annual mo.

tiouj

The Earth ap-
pro Acheth or rece-
deth f ram the fi4:'
ed fiars of the E-
clipttck^the (jHan-^
tity of the Di^me'
ter of the Gr^nd
Orb.

The fiarsnear^
to us make
greater differences
than the more r?-
Wote,

fheEpihgtiSof
the Phasnomena
of the fixeT (idri
CM fed by the an»^
nu4l motion of the

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

G.G

ALi Li?^ us, his

me:

In olfjeBs far
remotCy Mndtumi'
noMii a fmalldp-
froach or reeeffion
U imfcrceftible.

tion , may be by us obferved in the fixed ftars to be of tw
kinds : The one is, that of their apparent magnitudes varied, ac-
cording as we, tranfported by the Earth, approach or recede
from the fame : The other (which likcvvifc dcpcndeth on the
fame acceffion and reeeffion) their appearing unto us in the
fame Meridian^ one while more elevated, and another while leffe.
Moreover, you tell us (and 1 underftand it very well) that the
one and other of thefe mutations are not made ahke in all the
ftars, but in fome greater, and in others Icffer, and in others not
^t all. The acceflion and reccflion whereby the fame ftar ought
to appear, one while bigger, arid another while leffer, is infenfi-
ble, andalmoft nothing in the ftars neer unto the pole of the E-
cliptick, but is greateft in the furs placed in the Ecliptick it fd^i
and indifferent in the m'termediate : the contrary happens in the
other difference, thit is, the elevation or deprclfion of the ftars
placed in the Ecliptick is nothing at all, greateft in ihofe neercft
to the Pole of the faid Ecliptick, and indifferent in the interme-
diate. Befides, both thefe differences aremoie fenfible in the
Stars neereft to us, in the more remote leffe fenfible, and
tliofe that are very far diftant wholly difappcar. This is, as
what concerns my felf j it remaineth now, as I conceive, ^^^^
fomethingbe faid for the fatisfafiion of Simplicius^ who, as I
believe, will not eafily be made to over-paffe thofe differences,
as infenfible that are derived from a motion of the Earth fo vaft,
and from a mutation that tranfports the Earth into places twice
as far diftant from us as the Sun.

Simp. Truth to fpeak freely, I am very loth to confeffe,thaC
the diftance of the fixed Stars ought to be fuch, that in them the
fore-mentioned differences fhould be wholly imperceptible.

S A L v. Do notthrow your felf into ablblute defpair, Sim{^^'
cim , for there may perhaps* yet fome qualification be found ^^"^
your difficulties. And firft, that the apparent magnitude of
ftars is not feen to make any fenfible alteration , ought not to be
judged by you a thing improbable, in regard you fee the gueifts
of men in this particular to be fo groffely erroneous, efpccially
looking upon fplendid objefts ^ and you your felf beholding
-z/.g. a lighted Torch at the diftance of aoo paces , if
pirbach nearer to you 3. or 4. yards, do you think that it
fhew any whit encreafed in magnitude? I for my partfht'^^^
not perceive it certainly, although it fhould approach
30. yards nearer j nay it hath fometimes happened that in feeing
l^cha light at that diftance I know not how to refolve whether
1^ came towards me, or retreated from me , when as it ^^^^^
\cV .^PP^^^cI^ iiearer to me. But what need I fpeak of this-
It tbc ielf fame sLcCeiKori and reeeffion (I fpeak of a diftance

twice

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

I A L O G U E

5^1

^^vice as great as that from the Sun to us) hi the fiar of Salnrfz is
almoft totally imperceptible , and in Jupiter not very obferva-
We, what (liall we think of the fixed ftars , which I believe you
will not fcruple to place twice as far off as Saturn} In M^rx,
Nvhich for that it is nearer to us

Simp. Pray Sir, put your felf to no farther trouble in this
P^i'ticular , for I already conceive that what hath been fpoken
touching the unaltered apparent magnitude of the fixed ftars may
Very well come to paffe , but what (hall we fay of the other dif-
ficulty that proceeds from not perceiving any variation in the
"mutation of afpea >

Salv. We will fay that which peradveriture may fatisfie
you alfo in this particular. And to make {hort , would you not

fatisficd if there fliould be difcovered in the ftars face muta-
^i^ns that you think ought to be difcovered , in cafe the annual
Motion belonged to the Earth ?

Simp. 1 (hould fb doubtleflc , as to what concerns this par-
ticular.

Salv. I could wifli you would fay that in cafe fuch a diffe-
rence were difcovered nothing more would remain behind, that
might render the mobility of the Earth qutttionablc. But al-
though yet that (hould not fenfibly appear, yet is not its mo-
bility removed , nor its imnAobillty neceflarily proved , it being
pofllblc, (as Copernicus affirmeth) that the immcnfe diftancc of
the Starty Sphere tendereth fuch very fmall Vhanomena unobfef-
vablc^ the which as already hath been faid , may poffibly not
have been hitherto fo niuch as fought for , or if fought for , yet
not fought for in fuch a way as they ought , to wit, with that
exaftncffe which to fo minute a punftuality would be neceffary;
which exaftnclTc is very difficult to obtain ^as well by reafon of the
deficiency of Afttonomical Inftruments, fubjeftto many altera-
tions, as alfo through the fault of thole that manage them with lefs
diligence then is requilitc. A ncceflary argument how little ere.
dit is to be given to thofe obfervations may be deduced from the
differences which we find amongft Aftronomers in affigmng the
places,! will not fay, of the new Stars or Comets, but of the fixed
fi^rs themfelves, even to the altitudes of the very Poles , m
^Wch, moft an end, they are found to differ from one another
^^ny minutes. And to fpeak the truth , who can in a Quadrant,
or Bextant,-that at moft (hall have its fidc^ 3. or 4. yards long,
alcertalnhimfelfinthe incidence of the perpendicular , or in the
airefiiou of the fiahts not to erre two or three minutes , which
in Its circumference fii all not amount to the breadth of a grain of
""Mylet } Bcfides that , it is almoft impoffiblc, that the Inftrument
ftould be made , and kept with abfdlutc e^taanefle. Ftolomey

ihcweth

7/ in the gxed
fiars CM jhm/d
difcover any an'
nnal mutatton^ the
minion ef the
Earth Tvoiild h
nndenidbU,

It it proved fi^p
fmaU credit is to%
given to Afiroim"
mical Inflrumen^t
in minute obftrvk*
tions^

•BraCcil Italian.

* Or MilU

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

3^^

Ptolomy ^'^ ''"f

trufito aft /»/hfi'
ment mdde Ar-
chimedes.

litftrumettts of
Tycho made wtth
j^reat ex pence.

what InflrH'
piems are apt for
vttfi exalb ohfer-
vation.

* Italian braces.

t^n exquifite
ebfervation of the
afproMch and di'
farture of the Sftn
from the Snrnmer
Solfiici.

%/i place decern'
wtodated for the
obfervat 'ton of the
fixed fldrs^ MS to
what C9ncers the
)innu4tt motion of
thtEArtb,

G. G A L 1 L ^ Li s ^ his S^^en:e.

flic wfcth his diftruft of a Spherical Inftrument compofcd by Ar-
chimedes hiimclf to take the Suns ingixflion into the yEqui-
noftial.

S I M But if the Inftruments be fo fufpitious , and the obfcr-
vations fo dubious , how can we ever come to any certainty ot
things , or free our felves from miiftakes ? I have heard ftrangc
things of the Inftruments of Tycho made with extraordihary co&y
and of his fingalar diligence in oblervations.

S A L V. All this 1 grant you , but neither one nor other oi
tl^efe is fufficient to afcertain us in a bufineffe of this importance-
I defirc that we may niake ufe of Inftruments greater by far, and
by far ecrtain^r than thofe of Tycho ^ made with a very fmall
charge j the fides of which are of 4. 6. ao. 30. and 50. miles ^ io
as that a degree is a mile broad, a minute prim. 50* yards, *
fccond but little lelFe than a yard , and in (hort we may without
a farthing expence procure them of what bigneffe we pleafe. I
being in a Countrey Seat of mine near to Florence , did plainly
obferve the Suns arrival at , and departure from the Sumifl^^
Solfticc 5 whilft one Evening at the time of its going down it ^P'
peared upon the top of a Rock on the Mountains ot Pictraf^^^f
about 6o- miles from thence 5 leaving dlfcovcrcd of it a fi^^lf
ftreak or filament towards the North , whofe Breadth was t\ot
the hundredth part of its Diameter ^ and the following Eveni^^?
at the like fetting , it (hew'd fuch another part of it , but notat'y
more fmall , a neccffary argument , that it had begun to tccci^,
from the Tropick ; and the regreflion of the Sun from the firft
the fecond obfcrvation 5 doth not import doubtleffe a fecond H^J'
nutc in the Eaft. The obfervation made afterwards with an
quifite Telcfcope, and that multiplyeth the Difcm of theS^^jJ
more than a thoufand times, would prove eafie, and wit''
delightful. Now with fuch an Inftrument as this, I woul^l ^^"^^
obfervations to be made in the fixed ftars , making ufe of f^^^
of thofe wherein the mutation ought to appear more coflfp*^^'
ous , fuch as are (as hath already been declared) themor^^^'
mote from the Ecliptick , amongft which the Harp a very g^^^[
ftar , and near to the Pole of the Ecliptick, would be very P^^^
per in Countries jfar North, proceeding according totheri?^'^'
ner that I fliall flicw by and by , but in the ufe of another ^
and I have already fancied to my felf a place very well a^^^P^^
For fuch an obfervation. The place is an open Plane ? "P?^
Which towards the North there rifeth a very eminent N^^^^^^
»n the apex or top whereof is built a little Chappel , fitiiat^^^^j^
and Weft , fo as that the ridg of its Roof may interfed at ^^S^j
angles , ti^^ meridian of fome building ftanding in the plane* ^
wilJ place a beam parallel to the faid ridg , br top of the

A L O G U E

111

om it a yard or thereabouts. This being placed , 1
vvill ftrckin the Plain the place iVom whence one of the ftars of
(Charts' s Waine , in pafling by the Meridian , comcth to hide it
felf behind the beam lb placed , or in cafe the beam fliould not
be lb big as to hide the ftar , 1 will finde a ftation where one
may fee the laid beam to cut the faid ftar into two equal parts j
cfFcft that with an * cxquifice Telcfcope may be perfeSly
diicerned. And if in the place where the fiid accident is difcover-
l^dj there were fome building , it Will be the more commodious ,
but if not , 1 will caufe a Pole to be ftuck very fall in the
ground 5 with fome fianding mark to direfi where to place the
anew , when ever 1 have a mind to repeat the obfervation.
*ne firft of which obfervations I will make about the Summer
^ojftice , to continue afterwards from Moneth to Moneth , or
^^fifn I (liall lb plcafe , to the dther Solfticc ; with which obfer-
vation one may difcover the elevation and depreflloq qjf the ftar,
though it be very fmall. And if in that operation it fliail hap-
P^'^ 5 that any mutation ihall difcover it felf , what and bt>w great
f^cnefit will it bring tb Aftronomy ? Seeing that thereby, bcfides
our being alTurcd 6? the annual mbtion , We may come io know
the grandure and diftance of the fame ftar.

Sagr. I very well compreherd your whole proceedings ^
and the operation fecmsto mefoeafie, andfo commodious tor
Ae jpurpole , that it may very rationally be thought , that either
Copernicus himfelf , Or fome other Aftrdnomer had made triat
of it.

S A L I judgthe quite contrary , for it is not probable,

that if any one had experimented if, he would not have men-
ticncd the event, whether it fell out in favour of this, or that
^^pinion 5 befides that , no man that I can find , either for this,
any other end, did ever go about to make fuch kn Obfcrvati-
^^^5 which alfo without an e^^aftTelefCopc could but badly be
^ftcaed.

Simp. I am fully fitisfied with what you fay. But feeing
it is a great while to night , if you dcfire that I fliall paflc
fame quietly , let it not be a trouble to you to explain unto
us thofc Problems , the declaration whereof you did even now
^equcfttftight be deferred until tcio morrow. Be^leifcdto grant
your promifed indulgence, and, laying afide all other difcoiir-
i^s, proceed to fliew Us, that the motions which Copernicus zCCigns
^^^"^^^rth being taken for granted, and fuppofing the Suii
and hxed ft^is Immoveable, there may follow the fame acci-
dents touching the elevations and depreflions of the Sun , touch-
ing the mutations of the Seafons, ^nd the inequality of daycs
^nd nights, c^c. in the felf fame manner , )uft as they arc with

Yy 6'

3^5

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545 G. C A L I L ^ u s, his Syfiemei

facility apprehended in the Ptolomaick^ Syfteme.

S A L V. 1 neither ought) nor can deny any thing that Sagred^
fliall requeft : And the delay by mc dclired was to no other endj
fave only that I might have time once again to methodize thofe
prefatory points, in my fancy, that ferve for a large •and plain de-
claration of the manner how the forenamed accidents follow,
wellin the C(?/?er/;/fii;/ pofition, as in the Ftolomaich^: nay, vvi^'^
t^tf Coperni- xciiich greater facility and fimplicity in that than in this. Whence
chU to h under- One uuy maniteitly conceive that Hypothetis to be as ealie to dc
ie^fOed''^'''^'' effeSedby nature, as difficult to be apprehended by the und^^""
^ ' ftanding : yet neverthelefle, I hope by making ufe of another
Necejfarj pre- kind of explanation, than that ufed by Copernicus^to render like-
poptw^s for the ^^jf^ ^j^^ apprehending of it fomewhat kiie obfcure. Which
€fthecof7fe^ne»ci/ that I ma^y do, 1 Will propole certain fuppofitions of thcmlelves
lil!!' ^"''^^ linown and manifeft, and they fliall be thefe that follow.

Firft, I fuppofe that the Earth is a fpherical body, turning
round upon its own Axis and Poles, and that each point afligne^
in its ifujperficies, defcribeth the circumference of a circle, ff^^^'
er or leffer, according as the point affigned fliall be neeref
farther from the Poles : And that of thefe circles the greateft
that which is defcribed by a point equidiftant from the laid P^^^^^
and all thefe circles are pa.rallel to each other , ^,nd Parallels
Will call therti. ]

Secopdly, Thelfcartli being ot" a Spherical Figure, and of an^>'
pacous fubftance, it is continually illuminated by the Sun, accor-
ding to the half of itsfurface, the other half remaining obfcur^?
and the boundary that diftinguiflieth the illuminated part fto^
the daf k^eijpg a grand circle^ we will call that circle the urfff^'
nator of the light,

Thirdjy, If the Circle that is terminator of the light (b^^^^
paffc by. the Poles of the Earth, it would cut (being a g"^^^
and principal circle) all the parallels into equal parts , but
paffing by the Poles, it would cut them all in parts unequal, e5^'
cept onl)^5the ciccle in the middle, which, as being a grand cir^^^
will be ciit ipto equal parts.

J^"F6urt^y, The Earth turning round upon its own P^^^^V
qiiantities^of dayes and nights are termined by the arches
Parallclsvihterfea^^ the circle, that is, the terminator f>y^^
light, and the arch that is fcituatc in the illuminated Hei«^*P ^
prefcribeth the length of the day, and the remaincr is the ^^^^
tity of the night.. . .

u A fUin Scheme Thefe things being prefuppofcd, for the more clear un ^
reprefentini th ftanding of that which remaines to be faid, we will lay it
f^T"'Tv^fr i^^^^S^^e. And firft, we will draw the circumference <f
S^c" circle, that (kali reprefent unto us that of the grand Orb defc^^^

Dialogue 111.

'^^d in the plain of the Ecliptick, and this we will divide into
four eqiul parts with the two diameters Capricorn Cancery and
l^tbra Aries-, which, at the fame time, (hall reprefent unto us the
four Cardinal points, that is, the two Solftices , and the two E"
quinoSials j and in the centre of that circle we will place the
Sun Oj fi}^^ and immoveable.

. J^et us nekt draw about the four points, Capricorn, Cartccr,

Libra and Aries, as centres, four equal circles, which reprefcrit

Unto us the Earth placed in them at four fcveral times of the

year. The which, with its centre, in the fpace of a yeat, pafTeth

trough the whole circumference, Capricorn, Aries, Cancer, Li-

t^ra, movhig from Eaft to Weft, that is, according to the order

of tile Signcs. It is already manifeft, that whilft the Earth is in

Capricorn, the Sun v^ill appear in Cincer, and the Earth moving The 4^

^^ng the arch Capricorn Aries, the Sun will fecm to move along ^^^ZTtn^^

^he arch Cancer Libra, and in flibrt, will run thorow the Zodiack according t9Q<i^^

Recording to the order of the Signes, in the fpace of a year ^ and permcus,

tHis arft affuniption, without all queftion, full fatisfaftion i§
g^ven for the Siins apparent annual motion under the Ecliptick.
Now, coming to the other, that is , the diurnal motion ot the
Earth in itfeif^ }t is necc^^ary to eftablirti its Poles and its Axis,
the which innft be underftood not'to be ereft perpendicularly
upon the plain of the Ecliptick, that is, not to be parallel to the
A5(is of the grand Oib,but declining from a right alngle q 3 dc-
gteesandanhalf or thereabouts, v^^ith itsNottli PqIs Xq^^^^^

G. G A L I L /i^ u his Syficmc}

the Axis of the grand Orb, the Earths centre being in the Solfti-
tial point of Capricorn. SuppoUng therefore the Terreftrial
Globe to have its centre in the point Capricorn, we will deferibc
its Poles and Axis A B, inclined upon the diameter Capricorn
Cancer 33 degrees and an half j fo that the angle A Capricorn
Cancer Cometh to be the complement of a Quadrant or Radius,
that is, 66 degrees and an half , and this indination muft be un*
derftood to be immutable, and we will fuppofe the fuperiour
Pole A to be Boreal, or North, and the other Auftral, or South'
Now imagining the Earth to revolve in it felf about the Axis A B
in twenty four hours, from Weft to Eaft, there (hall by all the
points afligned inits fuperficies, be circles defcribed paralleU^
each other. We will draw, in this firft pofition of the Earth,
the greateft C D, and thofe two diftant from it^r. 33. and »^
half, E F above, and G M beneath, and the other two extreaJi*
ones IK and L M remote, by thofc intervals from the Poles A
and B and as we have marked rhefe five, fo we may imagine i^^"
numerable others, parallel to thefe, defcribed by the innuincr^'
ble points of the Terrcftrial furface. Next let us fuppofe th^
Earth, with the annual motion of its centre, to transferre it
into the other places already marked ; but to paffe thither in f^^.
a manner, that its Own Axis A B fliall not only not change in^^'*"
nation upon the plain of the Ecliptick, but fliall alfo never vary
dir«aion ^ fo that alwayes keeping parallel to it felf, it ^^l
continually tend towards the fame part of the Univerfc, or, |*
you will, of the Firmament , whereas, if we do but fuppofe
prolonged, tt will, with its extrcam termes, dcfigne a Circle f
raltel aja4 equal to the grand Orb, Libra Capricorn Aries Cancel*'
as the fupi^riour bafeof a Cylinder defcribed by it felf in tbe^J^'
imal wotion above the inferiour bafe, Libra Gapricdrn ^^^f
Cancer. And therefore this immutability of inclination
wingj we will dcCgn thefe other three figures about the centf^^
Aries,, Cancer, and Libra , aJikc in every thing to that fir^^^
fcrih^dab^wt the centre Capricorn. Now we will confidcr tP^
firft figure of the Earth, in which, in regard the Axis ^
cHn^dfrpm perpendicularity upon the diameter Capricorn Can-
cer 33 degrees ai;Kj an half towards the Sun O, and the arch A
being alfo 23 degrees and an half, the illumination of the
willillirf^atc theHemifphercof the Terreftrial Globe ^^f^^J?
towards the Suxi (of which, in this place, half is to be ft^^) ^
vided from the pbfcure part by the Terminator of
IM,; by which the parallel C D, as being a grand circle, ft^^
come to be divided into equal parts, but all the reft into parts u^^
tqu^l i being that the terminator of the light I M pafleth
by tn^irp0ks,A.B^andthe paraUel I K, together with all the re*]

defcribe»

I ALOGUE.

11.

^foibcd within the fame, and ncerer to the pole A, fliali wholly
^ included in the illuminated part ^ as on the contrary, the op-
pofite ones towards the Pole B, contained within the paral-
lel L M, fliali remain in the dark. Moreover, the arch A I be-

equal to the arch F D, and the arch A F, common to tliem
t>oth, the two arches I K F and A F D fliall be equal , and each
f quadrant or 90 degrees/ And becaufe the whole arch I F M
^ * femicircle, the arch FM fliali be a quadrant, and equal to
theotherFKIi and therefore the Sun O fliall be in this fiate
the Earth vertical to one that ftands in the point F. But by
the revolution diurnal about the ftanding Axis A B, all the points
^f the parallel E F pafli'e by the fame point F : and therefore ia
^'iat fame day the Sun, at noon, fllall be vertical to all the inha-
bitants of the Parallel EF5and will feem to them to defcribe in its
apparent motion the circle which we call the Tropick of Cancer.

to the inhabitants of all the Parallels that are above the pa-
rallel E F, towards the North pole A, the Sun declineth from
their Vertex or Zenith towards the South h and on the contrary,
all the ii>habitants of the Parallels that are beneath E F, to-
wards the Equinoftial C D) and the South Pole B, the Meridian
Sun is elevated beyond their Fer/ ex towards the North Pole A.
Next, it is vifible that of all the Parallels, only the greateft C D
is cut in equal parts by the Terminator of the light I M. But
the reft, that are beneath and above the faid grand circle, are all
interfered in parrs unequal ; and of the fuperiour oifts, the fe-
^idiurnal arches, namely thofe of the part of the Tcrrcftrial fur-
face/illuftrated by the Sun, are bigger than the fcminodurnal
ones that remain in the dark : and the contrary befalls in the
remainder, thit are under thegrelt one C D, towards the pole B>
^f which the femidiurnal arches are lefler than the CiminoAarnsily
is like wife apparently manifeft,tHat the diflferences of the faid
^ches go augmentitJg, iccordkig as the Parallels are ncerer to
^he poles^ till fuch time as the parallel 1 K comes to be wholly in

part illuminated, and the inhabitants thereof have a day of
^^cnty four hours long, without any night j and on the contrary,

Parallel L M, roMaining all in obfcurity , hath a night of
twenty four hours, without any day. Come we next to the
jWrd Figure of the Earth, placed with its centre m the point
G^ncQrt>vheretheSunfeemeth tobe in the firft point of Ca-
P/^corn. We have already fecn very manifeffly, that by reafon
^7 Axis A B doth not chinge inclination, but continueth paral-
lel to it felf, the afpca ^nd fituationof the Earth is the fame to
an hair vtith that in the firft Figure •, fave onely that that Hcmi-
Iphere which in tlie firft was illuminated by the Sun, in this rc-

Wmeth obtcnebratcd, and that gojneth tQbclumuiOtt^, which
' the

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2°K.B. 9,163

3fS Gal I L ;e il s , his Sypeme.

the fii'ft wXs tenebrous : whereupon th^t which happened before
concerning the differences of dayes and nights, touching the
dayes being greater or leffcr than the nighrs, now fiills out quite
contrary. And firft, we fee, that whereas in the firft Figure the
circle I K was wholly in the light, it is now wholly in the dark^
and the oppofitc arch L M is now wholly in the light, which
was before wholly in the dark. Of the parallels between the
grand circle C D, and the Pole A, the fcmidiurnal arches are noW
leffcr than the feminodurnal, which before were the contrary-
Of the others likewife towards the Pole B, the femidiurnal arch-
es are now bigger than the feminodurnal, the contrary to what
happened in the other pofition of the Earth. We now fee the
Sun made vertical to the inhabitants of the Tropick G N , and to
be dcpreffed towards the South, with thofe of the Parallel E F?
by all the arch E C C, that is, 47 degrees and in fumme, to haVC
paffed from one to the other Tropick, traver(]ng the Equinoflialj
elevating and declining in the Meridians the faid fpace of 47 de-
grees. And all this mutation is derived not from the inclination
or elevation of the Earth, but on the contrary, from its not in-
clining or. elevating at all h and in a word, by continuing always
in the fame pofition, in refpefl of the Univerfe, onely with tu^^'.
• ing about the Sun fituateiu the midft of the faid plane, in which
itmovcth it felf about circularly with its annual motion.

And

,y{n AimirMe here IS to be notcd 311 admirable accidcnt, wliicli i« that like f
l::t^^l!^^ S^.^^if Earth confcrving the fame diredion towards th^

if the Earths ^xt4 Univerie, or we may fay, towards the higheft Sphere of the fixed
flars, caufeth the Sun to appear to elevate and incline fo great a
fpace, namely, for 47 degrees, and the fixed Stars to incline or e^
levate nothmg at all ; fo, on the contrary, if the fame Axi^
the Earth fliould maintain it felf continually in the fame in^H^^^'
tion towards the Sun^ or, if yoii will, towards the Axis cf
Zodiacki no mutation would appear to be made in the Sun about
its elevating or declining, whereupon the inhabitants of one an^l
the iame place would alwayes have one and the fame difference
of dayes and nights, and one and the fame conftitution of Sea-
fons, that is, fome alwayes Winter, others alwayes Sumi^^'''
others Spring, Sfc. but, on the contrary, the alterations in f''^
fixed Stars would appear very great, as touching their elevati^"^
and inclination to us, which would amount to the fame^7
grces. For the underftanding of which let us return to confi^^^
the pofition of the Earth, in its firft Figure, where we fee
Axis A B, with the fuperiour Pole A, to incline towards the Sun?
out m its third Figure, the fame Axis having kept the fame dire-
ction towards the higheft Sphere, by keeping parallel to it fell>

HiCiine^ nalonger towards the Sun with its fuperiour Pole A, but

^ on

Dialogue. III.

•^1 the contrary recliaes froiA its fornier pofition^r. 47. and in-
•^'•neth towards the oppofice part, fo that to reftore the fame in-
clination of the faid Pole A towards the Sun, it would be rcqui-
'ttc by turning round the Terreftrial Globe, according to the
circumference A C B D, to tranfport it towards E thofe fame
2''-47. and for fo many degrees, any whatfoever fixed ftar ob-
served in the Meridian, would appear to be elevated, or inclined.
Let us come now to the explanation of that which remains , and
t us confider the Earth placed, in the fourth Figure, that is,
with its centre in the firft point of Libra*, upon which the Sun
Will appear in the beginning of Aries. And becaufe the Ams of

*e Earth, which in the firft Figure is fuppofed to be inclined up.
^« the diameter Capricorn Cancer, and therefore to be rtP that
fame plane, which cutting the pliiHe of the^nd Orb, accor-
•^'ng to the line Capricorn Cancer^ was ercaed perpendiciiUrly
"P«n the fame, tranfpofed into the: fourth Figure, and mamta,-
«ed, ashath alwaye^been faid, parSillel to it felf , it (hall come
l« be in a plane in like manner fcreftcd to the fuperfiaes of
Ae Grand Orbe, and parallel to the plane , which at ri^t
angles cuts the fame fupetficies, according to the diameter Ga.
pncorn caflcer. An^ therefWc 'ffee line which goeth trom
centre of the Suniie to the centre of the Earth, that is,
y Libra , ftaU be perpendicular to the Axis B A : but the
lame line -vvhich goeth from the centre of the Sannc to the
«entrc of the Earth , is >l#ay€S pcipeftdignlar to ***

G. G

tk that is the Tc

A L 1 L ^ u s , his SyPen.e.

CHCle that is the Terminator of the light ; therctorc
circle fliall paffe by the Poles A B in the fourth figure , and
in its plain the Axis A B (hall fall , but the greateft circle pafling
by the Poles of the Parallels, divideth them all in equal parts}
therefore the arches I K , E F, C D, G N, L. M , Aall be all
femicircles, and the illumiu'd Hemifpherc (hall be this which
looketh towards us , and the Sun , and the Terminator of the
l»ght /ball be one and the fame circle A C B D , and the Earth
being in this place fliall make it Equinoflial to all its Inhabitants.
And the »a«e happeneth in the lecond figure , where the Earth
having its illuminated Hemifphere towards the Sun, iheweth us
the other that is obfcure , with its nofturnal arches , which in
like manner are all femicircles, and confequently here alio it
makcth the Equinofiial. Andlaftly in regard that the line pro-
duced from the centre of the Sun to the centre of the Earth, is
perpendicular to the Axis AB, to which the greateft circle of
theparallelsCD, islikewife ered, thefaid line O L,/-ni ftall
palle of neceflity by the fame Plain of the parallel C D cutting
its circumference in the rnidft of the diurnal arch C D i
therefore the Snn fliall be vertical to any one that fliall ft*"*^
whert that intcrfeaion is made ; but all the Inhabitants of t^lt
Parallel (hall paflb the fame , as being carried about by t^e
Earth* diurnal convcrlion ; therefore all thef upon that iiJ
fliall have the Meridian Sun in their vertex. And the Sun at ih^
fame tune to all the Inhabitants of the Earth fliall feem to dc
"""u'^'Tu ''""'^ ^ EquinoaiaT f urtl^nnor.
Polar circles I K and L M , ..the one is wholly in the light , i^"^
the other wholly in the dark i but when the Earth is in the E^-^'
noSiaJ points, the halves of thofe fame polar circles are«nt'«^
bght, the remainder of them being in the dark ; it fiiould
bebard toundciift;ind , hovythat the Earth ^. or. from Cane";
(yfh^9 theparaUfl IK is wjioUy in the dark) to L..,one pa'i
the parallel towards the point i,l?eginneth to enter into the light-
i I- J" 7".T^''''~i » M beginneth to retreat tir

wardMjiq.Pole A&,Miterleailig the circle ACBD nolonger iti l^'
but m'twD othcr points falling between the terms I A and MAf
the.itrches lA and .M B ; whereupon the: Inhabitants of the circk
bcgpi-^en;,^ th^^light, and the other Inhabitants of thecirck
L M to partake of night. And thus you See that by tvfo fil»P'*
motions made in times proportionate to thqir bigneffc* , and
J^ntrary to one another, but performed , as all others that be-
to th^'^''^^'' mundane bodies, from Weft to EaftafligneJ
tUnf^ Pl^"''^"'^ G^°^^> adequate reafons are rendrcd of »11
taoWi rp^nom,„^ ^^ appearances , for the accommodating f

which

fame

Dialogue HI.

^hichto the {lability of the Earth it is ncceflary (forfaking that
^ynietry which is obferved to be between the velocities and mag-
'^itudcs of moveables) to afcribe to a Sphere , vaft above all
others , an unconceiveable celerity , whilft the other kffer
Spheres move extream flowly ; atid which is more, to make that
"potion contrary to all their motions and, yet again to adde to
the improbability 5 to make that fuperioiir Sphere forcibly to
anlpQrt all the inferlonr ones along with it contrary to their
Proper inclination. And here I refer it to your judgment to de-
^crmirie which of the two is the moft probable.

^AGR. Tome, as far as concerneth fenfe , there appeareth
^.^ iinall difference betwixt the fimplicity and facility of opera-
^;^"geffeas by the means affigned in this new conftitution , and
^ inultiplicity , confufion, and difficulty , that is found in the
*«cient and commonly received Hypothecs. For if the Univerie
difpofed according to this multiplicity , it would be ne-
ellary to renounce many Maximes in Philofophy commonly re-
^^ived by Philofophers , as for inftance , That Nature doth
"ot multiply things without neceffity j and, That She makes ufe
the moft facile and fimple means in producing her effefts ;
*nd. That She doth nothing in vain, and the like. I do confeffe
that I never heard any thing more admirable than this , nor can I
believe that Humane Underftanding ever penetrated a more
fublime fpeculation. 1 know not what Simplkim may think
of it. ^

S I M P. Thefe (if I may fpeak my judgment freely) do feem
fauT^ ^''^^^ Geometrical fubtilties which Anjlotle finds

mil K iT*? ^^"^^^ ' ^^^^ accufeth him that by his too
^iucn Uudymg of Geometry he forfook folid Philofophy ^ and I
ave known and heard very great Penpatetick^ Philofophers to
Uiwadc their Scholars from the Study of the Mathematicks , as
^ ofethat render the witcavilous, and unable to philofophate
,^11 i an Inftitute diametrically contrary to that of Plato ^ who
^ J^inittcd uoneto Philofophy, unleffe he was firft well entered in
' Geometry.

deh ^ ^ ^* ^ commend the policy of thefe your Pcripatetickj' , m
jj^^^^^5*^g their Difciplcs from the Study of Geometry, for that
r ^ art more commt dious for detcfting their fallacies j but
much ^ ^"^ey differ from the Mathematical Philofophers , who
the c ^^^^ willingly converfe with thofe that are well verft in
deftk^^^^^^ Peripatetick Philofophy , than with thofe that are
ftinpi '(hu^ ^^^^ knowledg, who for want thereof cannot di-
melb f T^^'''^^^™^^^^^^^™^- ^"^P^^^^gbythis, tell
J^fFefied r k what are thofe extravagancies and thofe too

thcW. '1 rL? ^'^^^tmake you think this Copernic an Sy Acme
*^Aeue plaufible ? > Z i o , .

3^1

iy4x tomes com^
Monlj admitted by
Phtlofopkers.

Ariftotle tax*
eth VUiofor (rcing
toe fiftdioffs »fGt-
9metry.

Pcripaterick Phi"
I'fophert condemn
the Study of Geo^

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2°K.B. 9,163

a G A L 1 L A u s , M Sjjlme.

Simp. To tell you true , I do not very well know perhaps,
becaule I have not lo much as learnt the realons that are by ftolo-
my produced, of thole effefts, Imean of thofe ftations, retrogra-
dations, acaffions, reccffions of the Planets v lengthenings and
fliortnings of day es, changes of icafons, &c. But omittuig the
confequences that depend on the fiift luppofitions , I find in the
fuppolitions themfelves no fmall diflSculties which fuppofitions,
if once they be overthrown, they draw along with them the ruine
of the whole fabrick. Now iorafmuch as becaufe the whole
module of Copernicus leemeth in my opinion to be built upon in-
firm foundations,in that it relyeth upon the mobility of the earth,
if this (hould happen to be diiproved, there would be no need o*
farther difpuce. And to difprove this, the Axiom of Arifiotl<^
is in my judgement moft fufficient , That of. one fimple body?
one fole fimple motion can be natural : but here in this cafe , to
Four fvcr^ti the Earth, a fimple body, there are afiigned 3. if not 4. morions?
mottonsajfigne^to ^jj y^j-y different from each other. For befides the ligh^

theEufth. motion, as a grave body towards its centre, which cannot be

nied it, there is affigned to it a circular motion in a great circle
about the Sun in a year, and a vertiginous converfion aboun
own centre in twenty four hours. And that in the next pl^
which is more exorbitant,^ which happly for that realon yoi^
over in filence, there is aferibed to it another revolution ^ooU
its own centre, contrary to the former of twenty four hours ?
and which finiOieth its period in a year. In this my underftan^'
ing apprehendeth a very great contradifiion.
•Xhe f^otion of S A L V. As to the motiou of defcent, it hath already been co^'
iefcent belongs not cludcd not to bcloug to the Tetreft rial Globc which did n^^'^^
to the ttrreflnaL ^. ^^^^j^ niotion5nor iievcr fliall do j but is (if there ^ ^

Globe * but to tts J ^ ^ . . ^ , ^CA^CS

ims' fuchathing) that propenlion ot its parts to reunite thcint^;'^

to their whole. As , in the next place , to *he Annual ^^^^^^^^
The annuAi and and the Diurnal , thefe being both made towards one wayy ^
dinrnai motion are ycry compatible , in thc fame manner juA as if we fliouW |^
3'^^' " Ball trundle downwards upon a declining fuperficies, it wonW^^
its defcent along the fame fpontaneoufly revolve in it felf
to the third motion afilgncd it hy Coperntcm , namely aboi^^^
felf in a year , onely to keep its Axis inclined and ^^^^j^j^g
towards the lame part of the Firmament, I will tell you a t
worthy of great confideration ; namely nt tantum abefi i^^\^^^\^a
it be made contrary to the other annual) it is fo far from'^^
£ver7pe.r.u^d any rcpugnance or difficulty in it,that naturally and "^'^^^^f.u^^^
l:bratedMy'^'' Moving caufe, it agreeth to any whatfoever fufpended and

7;^^;;/'; ted body, which if it fliall be carried round in the circumtete
ZTu/rcquirethof of a circle, immediate of it felf, it acquireth a convcrfion ao ^
it fjfamothn^n j^g qwh Centre, contrary to that which carrieth it about, l

it felf contrdrj to ' ^ . ItlC**

that.

bl ALOGUE. I IL

^"ch velocity, that they both finifh one revolution in the fame
^^nieprccifcly. You may fee this admirable , and to our pur-
Pofe accommodate experience, if putting in a Bafon of water a thhb^[llfibiy
^^11 that will fwim 5 and holding the Bafon in your hand , you jhnvt that n^o con-
Jiirn round upon your toe , for you fhall immedi^tly fee the Ball '""^ ^('ommay
^^g»n to revolve in It fell With a motion, contrary to that of the rhrfamcmovc-

and it lhall finifh its revolution , when that of the Bafon it
™Hfinini. Now what other is the Earth than a penfil Globe
'orated in tenuous aiid yielding aire , which being carried a-
out in a year along the circutnference of a great circle , muft
^eeds acquire, without any other niovcr, a revolution about its afcl!(fedtJ7h/^ .
®wn centre, annual, and yet contrary to the other motion in like ^''^^^ *^ rathtrA
"^^'^ner annual ? You fliall fee this cffea I fay, but if afterwards '^^^^

more narrowly confider it , you (hall find this to be nO real
^^*i^g, but a mccr appearance ; and that which you think to be
^ revolution in it felf, you will find to be a not moving at all,
a continuing altogether immoveable in rcfpe6i: of all that
which without you,and without the vcffel is immoveable : for if in
^hat Ball you ftiall make fome mark, arid coinlidcr to vvhat pact of
^he Room where you arc, or of the Field , or of Heaven \t is
fituate , yoU fliall fee that mark in yours , and the vefTels revolu-
tion to look alwayes towards that fame part j but comparing it to
the veffcl and to your felf that are moveable, it will appear to go
altering its direftion , and with a motion contrary to yours , and
^at of the velfcl, to go feeking all the points of its circumgyra^
^JOn i fo that with more reafon ydu and the bafon may be faid
turn round the immoveable Ball , than that it mdveth round
>n the bafon. In the fame manner the Earth fufpcridcd and H-
rated in the circumference of the Grand Orbe, and fcituate ih
iich iort that one of its notes, as for example, its North Polejioo-
^^th towards luch a Star or other part bf the Firmfament,it always
^^^peth direfted towards the fame i ' although carried rotand''«t>^
annual motion about tile circumference of the faid Gtaild
Orbe. Xhis alone is lufficient to make the Wonder ceafe, ^nd
remove all difficulties. But what mllSimpUctusbf y if txy
^hrs^ non-indigence of the co-operating caufe we fttould ' addc
admirable intrinfick vertue ef the Terreftrial Globe, of look-
J^g With its determinate parts towards determinate parts of the intern vert of tht
^irmamcnc, I fpcak of the Maenctick vertue ooiiftadtly pattlc^ urrcfiruicuhof
P;.^^^ by any whatfoever piece of Loade-ftorie. And if ev^y
minute particle of that'Sionc have in it fuch a vertue, who Will Hr^f^«.
S^eftionbutthatthe fame more powerfully f efides in thfs whole ItrS'^
Iwuu ^^"^^^ ^ abounding in that Magnetick matter, k-nd L^^dc-My
wnich happily it f^lf^ as to its internal and primary fubftariccv
^^othingelle butahugemalTeof Loade.ftonc» - - / ^

Zz i S IMI*.

3^4

* An eminent
DoaorofPhyHck,
ourCouncrcyman,
born at Colchefler^
and famous for this
his learned Trca-
tife, pi|bliflied a-
bout 60 years fince
at London , The
Magnetici^ 'Phi-
lofofhj of William
Gilbert.

The THjtUani*
mitj of PofHfitr

mtt.

G; G A L I L A u s , his Sjfleme.

Simp. Then you are one of thofe ir icems that hold the Mag^
nctick Phylofophy William * Gilbert.

S AJf V-,. I am for certain, and think that all thofe that have
ferioufly read his Book, and tried his eKperiments, will bear me
company therein ^ nor (hould I defpair, that what hath befallen
me in this cafe, might poflibly happen to you alfo, if fo be a cu-
liofity^ like to mine, and a notice that infinite things in NaturJ?
are ftill conceafd from the wits of mankind, by delivering yoi^
from being captivated by this or that particular writer in natural
things, fliouldbut flacken the reines of your Reafon, and mol-
lifie the contumacy and tenaceoufneffe of your fenfe , fo as that
they would notrefufe to heaiken foinetimes to novelties never
before fppken of. Biit (perqait me to ufe this phrafc) the piifiH^'
nimi^yof vulgar \Vits iscome tothatpaffe, that not only lil^^
blind; m'ed, they make a gift, nay tribute of their own aflcnt to
whatfoever they find written by thofe Authours, which in tb^
infa^icy of their Studies wejrc laid before them, as authentick by
their Tutors, but rcfufe to hear (not to fky examine) any ^ev^
Propofition or Prjcibleme, although it not only never hath heefl
confuted, bat not ip much as examined or confidcred by f'^^!^
Aiichourf . Amolngft whichy one is this, of inveftigating vvbat
thetrue^ proper, pjcimary, interne, and genera] matter zt\di^^'
fiance of tWow^Terreftrul Globes For although it never calU^
into the mind either of Ariflotle^ or of any one elfe, before /f^''
liam Gilbert tQ tUnk that itonight be a Magnet, fo far are A^^^
ftotJe atid the reft from confuting this opinion , yec never thelef^
I. have met with many, that at the very firft mention of it, a5 »
Hdrfe it his own fliadow, have ftart back, and refufed to
courfe thereof, and cenfured the conccipt for a vain Chyrrt^^'^
ye^b- for foleinn niadnefle ; and its pofllble the Book of Oill^^^^
h^.rtcver come IP my haiids,if a Peripatctick Philofopher,of
fa|ni:, a^ I bdkve, 'to free bi§ Library from its contagion,

> i > .1^0 ingenup^fly confeffe my fclf to be one ^^j
tl?dfp vulgar Wif^. and never till within thefe fcw dayes that *
hlite ticien ^drpijtted to a fharein your conferences, could I P^*
tend toMve an^the leaft withdrawn from thofe trite and pt^P^'
latjpatJhs3,,yetyfPfallthdt,'I think Ihavc advantaged my
m^^h, fa5 'that>l eould without much trouble or difficulty?
th^vrpngbnefTes of thefe mv^h and fantaftical opinions.
! r.5A t V. If that which Gsi76tfrrvv'riteth^be^ruc, then is it i^^'
Pmion, but thefubjca of /Science nor is it new, but^s afl^fj^^
^5<iic Earth it feJf^ nbr caii iit (being true) be rugged ot ditn-
**t:Plaia and cafi« ^ and when yx3u pleafe»I ihall make j^^
tccl the fame in youc haft^^ffor th*tyj^aof ,your felf fancy it

Dialogue

HI.

565

bcaChoft, and ftand in fear of that which hath nothing in it of
dreadfully like as a little child doth fear the Hobgoblin, without
knowing any more of it, favc the name , as that which befides
the name is nothing.

Simp. 1 fhould be gUd to be informed, and reclaimed from
3n errour.

S A L V. Anfwer nle then to the queftions that I (hall ask you.
And firft of all, Tell me whether you believe, that this our Globe,
^hkh we inhabit and call Earth, confifteth of one fole and Am-
ple matter, or elfe that it is an aggregate of matters different

f'^om each other.

S I M P. I fee it to be compofed of fubftances and bodies very
different^ and firft, for the greateft parts of the compofition, Qlohl c.mpcf/dlf
I fee the Water and the Earth, which excreamly differ from one fundrj mutters.
another.

S A L v. Let us, for this once^ lay afide the Seas and other Wa-
^^ts, and let us confidcr the folid parts, and cell me, if you think
tlieiTi one and the fame thing, or eife different.

Simp. As to appearance, I fee that they arc different things,
^hcre being very great heaps of unfruitful fands, and others of
fruitful foiles i There are infinite fliarp and fteril mountains, full
Of hard ftones and quarries of ftveral kinds, as Porphyrc, Ala-
llafter, Jafpcr, and a thoufand other kinds of Marbles : There
arc vaft Minerals of fo many kinds of metals j and in a word,
fuch varieties of matters, that k Whdle day would not fuflSce on-
'y 't6 enumerate them.

Sal v.. Now df all thefe different matters , do you think,
^hat in thb compofition of this grand maffe, there do concur por-
tions, or elfe that atnongft them all there is one part that far ex-
ceeds the reft, and is as it were the matter and fubftance of the
^^^menfe lump >

S I M P. tbelieve that the Stones, Marbles, Metals, Gems, and
fo many other feveral matters are as it were ]ewels, and ex-
^^fiour artel fuperfitial Ornaments of the primary Globe, which
^f^/gtofTe, as I believe, doth Without compare exceed all thefe

put together. . u r

^Salv. And this •principal and vaft maffe, of which thofe
™ngs aboi^e named are as it were excreffences and ornaments, ot
^Hat matter do yoU think that it is compofed

1 think that it is thefimi?le, or leffe impure element of

Earth.

S A lV: But what do you uriderftand by Earth? is it haply
that whichjs difperled all over the fields, which is broke up with
Mattoclcs and Ploughs, wherein we foWc come, and plant fruits,
^lid in which great bofcages grow iif>, the help of cul-

tare

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2°K.B. 9,163

866 G. G A iiLJ^uSy his Syficrnc.

ture, and which is, in a word, the habitation of all animals, an(J
the womb of all vegetables ?

Simp. Tis this that I would affirm to be the fubftance of this
our Globe.

S A L V. But in this you do, in my judgment, affirm that which
is not right : for this Earth which is broke up, is fowed, and is
fertile, is but one part, and that very Imall of the furface of the
Globe, which doth not go very deep, yea, its depth is very fmall>
in comparifon of the diftance to the centre ; and experience
/Iheweth us, that one fliall not dig very low, but one fliall finde
matters very different fiom this cxteriour fcurf , morefoli^^J
not goodfor the produitionof vegetables. Befides the interne
parts, as being compreflTed by very huge weights that lie up^^
them, are, in all probability, flived, and made as hard as any
hard rock. One may adde to this, that fecundity would be in
vain conferred upon thofe matters which never were defigned to
bear fruit, but to reft eternally buried in the profound and dark
abyffes of the Earth.

Simp. But who fliall aflure us, that the parts more inwafd
and near to the centre are unfruitful ? They aifo may, perhaps?
have their produftions of things unknown to us ?

Sal v. You may afwell be afliired thereof, as any man el^
as being vefy capable to comprehend, that if the integral bodi^*
of the Univcrfe be produced onely for the benefit of Mankind
this above all the reft ought to be deftin'd to the fole convcnie^^'
ces of us its inhabitants. But what benefit can we draw i(0^
matters fo hid and remote from us, as that we fliall never be ^'
J^i"u::X::i ^^^^^ ^^^^^f^ ^^^^ ^ Therefore the interne fubftance oi
Gioh mufi of r,c^ ^^^^ ^ur Globc canuot be a matter frangible, difllpable, and i^^'
'''^Oc^u'^^'^' ^^^^ fupcrficial part which we call "Earth-

it muft, of necefllty, be a moft denfe and folid body , and ^
word, a moft hardftone. And, if it ought to befo, what f^^^^.^
IS there that fliould make you more fcrupulous' to believe that
is a Loadftone than a Porphiry, a Jafper, or other hard Ma^'
ble? Happily if Gi//^rr^ had written, that this Globe is all co^'
*Of which with potinded within of Pietra Serenay ov oi Chalcedcn, thepaf^^^'^
the Latin cranfla- would havc fcemed to you leffe exorbitant >

tour, I muft once o t-i ^ i_ r i . . . ^nfC

more profcffc my i>i M p. That the parts ot this Globe more intern arc i^^^'
fclMgnoraiu. compreflTcd , and fo more flived together and folid , and ^^^^
and more fo , according as they lie lower, I do grant ,
Tikewife doth Arifiotle , but that they degenerate and becc>^ ^
other than Earth , of the fame fx)rt with this of the fupef^^^^^
P^rts, t fee nothing that obliege h me to believe.

^'"H^r'fv.titi^ertook not this difcourfe with an intent to ff^^^
demonftr^tiyely that the jprimary and real fubftance of thisj^^

Dialogue

HI.

5^7

Olobe Is Load-ftonc i but oncly to ftew thit no reafon could Be

unwilling to grant that it isot

one

given why one (liouU be more

Load-fto

than of lotne other matter. And if ybu vvill but o,,r ghh r,o»U

fcrioaa7ronfider, youlhall find that it ' .J^,' ^.t^f./

onefok, pure, and arbitrary name, hath moved men to thmt J^^^^^ ^
'hat it conf.fts of Earth •, and that is their having made de com- w i«» e;_-
■nonly f,om the beginning of this word Earth , as well to figni- - -
fi« that matter which is plowed and fowed , as to name this our
Globe. The denomination of which if it had been taken from
ftone , as that it might as well have been taken from that as
from the Earth • the faying that its primary fubftance was Itone,
Would doubtleffe have found no icruple or oppofition in any
nian- And is fo much the more |»robable, in that I verdy be-
'i^ve, that if one could but pare off the fcurf of this great Globe
taking away but one full thoufaud or two thouiand yavds ; and
afterwards feperate the Stones from the Earth , the accumulati- ^
on of the ftoncs would be very much bigcr than that of the fer-
tile Mould But as for the reafons which concludcntly prove de
U^io, that is our Globe is a Magnet, I have mentioned none of
them nor is this a time to alledg them , and the rather , for that
to yo^r benefit you may read them in Gilbert , onely to encou-
nL YOU to the perufal of them , I will fet before you, m a fimi- ^
litude of my own , the method that he obferved m his Philolo-

Gilbert <■« hit Phi^

phy. 1 know you underftand very well how much the know- hfifhj.
Icdgof the accidents is fubfervicnt to the inveftigation of the
fubftance and cfTencc of things therefore I dellre that you
Would take pains to informe youtf felf well of many accidents and
properties that are found in the Magnet , and in no other ftone,
or body; asforinftance of attra&ng Iron , of conferring up- ^„
«n it by its fole prefencc the fame virtue , of conimun.cating
I'kewife to it the property of looking towards the Poles , a.s it
^Ifodoth it felf .^nd moreover endeavour to know by trial
^hatitcontainethin it a virtue of conferring "P^n^l^^e ^e^^^^^^
««dle not onely the diteaion under a Meridian towards the
P^l^s , with an Horizontal motion , (a property a long time ago
Wn)but a new found accident , of declining O^^^^^ ^^^^^
«"der ihe Meridian before marked upon a little %hericam^^^
of declining I fay to determinate «»f '^^.^J^JJ^^ X'^^^"
^^tdingas that nebdle is held nearer or f^^^^^" j^^^^^^^^^^^
that upon the Pole it felf it eredeth Pf Pf''^,^^^
1" the middle parts it is parallel to the Axis- J""^"^^^^^^
*=»te a proof to be made , whether the virtue of attrafting lron»
refidingmucCre vigo: oufly about the Poles , than about the
middle parts, this force be not notably more vigorous in one
Pole than in the other, and that in all pieces of Magnet -, the

j68

a G

AL IL^US

erne.

ftrUr
a Magnet

ftiongerof which Poles is that which lookcth towards rthe South.
Obferve, in the next place, that in a little Magnet this South and
more vigorous Pole, becomcth weaker, when ever it is to take
up an iron in prefence of the North Pole of another much big-
ger Magnet : and not to make any tedious difcourfe of it, alTet-
tain your felf, by experience, of thefe and many other properties
defcribed by Gilbert^ which arc all fo peculiar to the Magnet, as
^"t'hurrt ^^^^ °^ ^^^^ with any other. matter. Tell me noW,
ufchh to h Simpl/cius, if there were laid before you a thoufand pieces of
^i^nrr. feveral matters, but all covered and concealed in a cloth, under
which it is hid, and you were required, without uncovering them,
to make a gueffe, by external fignes, at the matter of each oi
them, and that in making triaj^ you (hould hit upon one th"
fliould openly ftcwit fcli to have all the properties by you alrea-
dy acknowledged to rcfide oncly in the Magnet, and in no other
matter, what ;udgment would you m;^e of the cflence of fucb »
body ? Would you fay, that it might ^ ? piece of Ebony, of
Alablafter, otTm. ^

S I M F. I would fay, without the Icaft ha^fifation, that it was »
pi?ce of Load-ftone.

_ SAtv. If itbefcfayrefolutely, that under this cover ai"^
Icurf of Earth, fiones, metals, water, &c. there is hid a great
Magnet, forafmuch as about the fame there may be feen by an/
one that will heedfully obferve the fanje, all thofe very accident*
that »gree with a true and vifiblc Globe of Magnet ; but if nO
more were to be fecn than that of the Declinatory Needle, which
bemg^amed about the Earth, more and ,nore indineth, a it

5' ^""^P.^Jf' '.r^ declineth lefle towards the E'
qumo&al, under which ,t finally is brought to an JE.mlibri'^'^^
It might ferve to perfwade even the moft fcrupulous judgment- I
torbear to mention that other admirable e/Fea, which is feofi'''/
obf^v^d in every piece of Magnet, of which, to us inhabitants
oi the Northern Hemifphere,che Meridional Pole of the faid Mag'
net IS more vigorous than the other ; and the difference is foun-l
greater, by how wich one recedethfrom the Equinoaiali and
under the Equ,noa,aI both the parts are of equS ftrenU but
notably weaker Bur, in the Meridional Regions, far diftan^
fi-om the Equinoa.aI,,tchangeth nature, and that i^artwhicht^
us was more weak, acquircth more ftrength than the other
all this I confer with that which we fee to be done bv a ^^11
piece of Magnet, in the prefence of a great one, the vcrtue o£
which fuperating the leffer,maketh it to become obedient to it,
anjaccprding as it i, held,either on this or on that fide the Equi'
whicK I u ^''%g'5^^ o"'^' "lakcth the felf fame mutations,
^ have laid arc made by every Magnet, carried on

fide

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D I A L O G U E J I L'

fidt^ or that ildc of thei

369

linbiftiall of the Earth.
"-^ A G R.. I waii perfwadcUi at the very firft reading of the iSodk

Gilbenjis m\d having met with a moft excellent piece of '
Magnet,!, for a long time, made many Obferv^tions, aiidal!
Worthy of extrcam wonder:^ but above all, that (eemeth ine ^'-/^ '^rc iron,
^eryftupendious of increaiing the faculty of taking up Iron To
much by arming it, like as the laid Authour tcach^th • and with
Fleming that piece of mi^ie,! multiplied its force iiv^uple propor-
and whbreas unarmed it fcarce took up nine ounces of
it being armed did take up: above fix pounds: And^ it
yoti have fecn this Loadftonc in the " Gallery of y6tir + orQofct rf
Serene Qmud Diih^t (to whofti 1 preferrted^4t) uplialdirig raricics.
little Ailchbrs ofWi:- -oj .- : l- , . \ -

Sa l v. I (aw it many times, and With great admiration /till
^at a little pioce of the like ftone gave me greater caufc of won-'
that is in the keeping of our Academick, which beitrg no
l^ore than of lix ounces weight, and fuftaining^ when unto^med,
hardly twb ounces, doth, when arm^d, take up t6o, ounces ' fo'
^sthat it is of 80. times more force armed than unarmed^ 'and
^^kes up a weight 0.6. times greater than its oWn ^ a much greater
Wonder than Gilbert could ever meet with, who writethj that lie
cpuld never get any Loadftone that could reach to take up 'foiK
limes its own weight, , :

S A G R. In my opinion, this Stone offers to t^^wit of mah a .
l*rge Field to Phylofophate in ; ahd I have many times thought
with my felf, how it can be that it conferreth on that Iron, whicK
^rmeth it, a ftrength fo fuperiour to its. own ; and finally, I finde
nothmg that giveth me rfatistaftion herein *, nor do I find any
'^^^g extraordinary in tkit which Gilbert writes about this parti-
cular 5 1 know not wJiether the fame may have befallen
JfOll.^ ..... ■ [ -K.! - : - ■ - -■ ■

^^^^ A L Vv l j^xtreamlyi praife, adinifej and envy this Authou^,
^J' that a cb|iceit fo ftupen4ious fliould come into his minde^
J^uching a thing handled by infinite fublime wits, and hit upon
y none of them : I think him moreover worthy of exttaordi-
^**^y applaule for the many new and true Gbfet vations that he
n^ade, to the difgraee of fo many fabulous Authours, that write
only what they do not know, but what ever they hear fpo-
by the foolifli vulgar, never feeking to affure themfelves of
. e fame by experience, perhaps, becaufe they are unwilling to
J«ai the bulk of their Books. That which I could have de*
^ ^^J^'lbert, is, that he had been a little greater Matbematici-
an, a»^d particyigjj.jy well grounded in G^<?«/e/r;, the praftice
WhercoUvould have rendered him lefs refolute in accepting thofe
ealons tor true Demonftratiom, which he pro4uCeth for true

A a a caufei

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2°K.B. 9,163

37®

The fir ft oh fit-
vers And, myenters
of things ought to
h admtred^

The true eaufe
of the multiplica'
tion of vert He in
the iMagnet , bj
means of the Ar-
ming,

Of AneweJfeG:
its Mcefary that
the caufe be Itk^-
wife new.

It is proved:,
that Iron eonftBs
«fpArts more fftb'
ttly purcy and com*
pA^ thAH the mAg^
ftett

JGr-G^L I L aus , hisSjpetrje.

Caufcs^lhe true conclufions obTeisced by himfelf. Which rca-
fons. (freely fpeaking) do not knit andls^nd lo faih as; t ho fe un-
doubtedly ought to do, in that of natural, neccffary, and lading'
conclufions may be alledgcd. And I doubt not, but that in pro-^
cefle of time this new Science will be pcrfe&ed with new obfcO'
vations, and, which is more, with true and neceflary Demonftra-^
tiqr^Sv Nor ought the glory of the firft Inventor to be thereby
diminiftied J nor do l leffeefteem, but rather more admjre, the
Inventor of thei Harp (although it may be fuppoled that theln^
ftruiiient at firft wa& but rudely framed, and more rudely fing^*^'
ed)<rf^a'fv anh^<l4rJed othpr Artifts, that in the infuing Ages red^*
ced.tlW;P^ ofeffiG(o to great perfcftion. And mcthinks, that h^*^
tiquity had very good realon to enumerate the firft Inventors^^*
the.Noble Arts apiongft the, Gods ^ (cetng that the common wi^^
haye^fp jittle cqriofity^ and are fo little regardful of rare and elc
gimt things, that, though they fee and hear them exercirated W
theexquifite profeflbrs of them, yet are they not thereby p^^'
fWfided:;tp a dcfire of learniitg them. Now judge, whether C^p^"
citiqs of this kind would ever have attempted to have found
the t^alyr^g of the Harp, or the invention of Mufick, upon
hint Q.fjjthe whiftling noife of the dry finews of a TortoiS)
froiQ'it^^ ftrikingt of ;fout Hammers.: The application to gf
inventions moved by fmall hints, and the thinking that under *
Pfim^ifjf ^ndchildift appearance admirable Arts may lie hid,
wt tb^ part of a trivial, but bf a fuper- humane fpirit. Now aJ**
fwering -^toyourdemands, 1%, that I alfo have long though]
upprjjWifaat inigfali .poflibly be. the caufe pf this (o tenacious
ppt^rrt^^nion, that we lee to be made between the one Iron tb*^
armedi ithe Magnet, and the other that conjoyns it felf unto
An(|;f|rft, we are certain, thatthe vertue andftrengthofthc/i^
doth not augment by being armed, for it neither attra*^*
^reat^r diftance, nor doth it hold an Iron the fafter, if betwce^^
and tl^arfltting or cap,a very fine paper, or a leaf of beaten g^^*
l?e intef^cjfed i nay , vvith that interpofition, the naked ft^
takes up more Iron than the armed. There is therefore no ^'^^
ratioq in the vertuey and yet there is an innovation in the cff^^'
Ai^d b^eM^fe its neceflary, thit a Hew efFeft have a new caufe>
it be inquired what novelty is introduced in the aft of taking
twith the cap or aritling, there is no mutation to be difcovere^ij
in the different contaft; forvvhereas before Iron toucht Load'
ftpnc, jiov^ Iron toiicheth Iron. Therefore it is neceflary to cot^'
cMe,.that the diverfity of contads is the caufe of the div^rfi^V
^£ cfFefls, And for the difference of contafts it cannot, as I
be d^riv^d: from any thihg elfe, fave from that the fubftance
the Iroil itf of ^^^^^ p^j^^^ ^^^^ cainpag

I A L O G U E.

Hi.

feet

it>

id-

rfl-

ity

^ ^!ian thofe of the Magnet, which are more groffe, impure, and
fare. From whence itfolloweth, that the luperficies of two I-
that are to touch, by being exquifitely plained, filed, and
"^irniflicd, do fo exaftly conjoyn, that all the infinite points of

one meet with the infinite points of the other i fo that the
filaments, if [ may fo fay, that coUcgate the two Irons, are many
^^ore than thofe that coUcgate the Magnet to the Iron, by reafon
that the fubftancc of the Magnet is more porous, and leffe com*
P^ft, vvhich maketh that all the points and filaments of the Load-
ftone do not clofe with that which it unites unto. In the next
P^^c^5 that the fubftance of Iron (efpccially the well refined, as
namely, thepureft fteel) is of parts much more denfe, fubtil,
and pure than the matter of the Loadftone, is feen, in that one
bring its edge to an extraordinary fliarpnefic, fuch as is that

the Rafor, which can never be in any great meafure efFcfted in
} piece of Magnet. Then^as for the impurity of the Magnet, and
being mixed with other qualities of ftone, it is firft fenkfibly
difcovered by the colour of fome little fpors, for the moft part
^^hitc \ and next by prefenting a needle to it, hanging in a
^^rcad which upon thofe ftonyneffes cannot find repofc, but
^eing attra(5cd by the parts circumfufed, feemeth to fly from

* thofe^ and to leap upon the Magnet contiguous to them : and
fome of thofe Heterogeneal parts are for their magnitude ve-
vifible, fo we may believe, that there are others, in great a-

'^undance, which, for their fmallnelTe, are imperceptible, that are
^iffeminated throughout the whole maffe. That which I fay,
(namely, that the multitude of contafis that are made between
ron and Iron, is the caufc of the fo folid conjunftion) is con-
Ij^rnicd by an experiment, which is this, that if we prcfent the
Iharpned point of a needle to the cap of a Magnet, it will ftick
fafter to it , than to the fame ftone unarmed : which can
P'^oceed from no other caufe, than from the equality of the con-
^^^s that are both of one fole point. But what then ? Let a

* Needle be taken and placed uponr a Magnet, fo that one of its
^'^l^tcmities hang fomewhat over, and to that prefent a NaiU to
yv^ich the Needle willinftantly cleave, infomuch that withdraw-
'"g the Nail, the Needle will ftand in fufpenfe, with its two
^ds touchiiig the Magnet and the Iron 5 and withdrawmg the

yet a little further, the Needle will forfake the Magnet i
Ptovided that the eye of the Needle be towards the Nail, and
the point towards the Magnet^ but if the eye be towards the
TlT in withdrawing the Nail the Needle will cleave to

tne Magnet ^ and this, in my judgment, for no other reafon,
lave onely that the Needle, by reafon it is bigger towards the
^ye, touchcth in much more points than its {harp point doth.

57t

A fepjihlt froof
of the impurity of
the Oii4£mct,

■ The Author
hereby meancth
the (^one
ftth not ill con-
fift of magnctick
maccer , buc thac
the whiter fpccks
being weak, thofe
other parts of the
Loadftonc df a
more dark & Con*
ftant colour, con-
tain all chat vertue
whcrewich bodicf
arc attracted.

* A common
fevying needle.

G. G A L I L u s , his Syfieme.

S A G R. Your whole difcourfe hath been in my judgment very
concluding, and this experiment of the Needle hath made flic
think it little infcriour to a Mathematical Demonftration y
I ingenuoufly confeffe, that in all the Magne tick Philofopliy ? I
never heard or read any thing, that with fuch ftrong reafons
gave account of its fo many admirable accidents, of whichj if
caufes were with the fame perfpicuity laid open , I know fl^t
what fw€eter food our Intellefts could defire.

S A L V. In fecking the reafons of conclufions unknown unto
us , it is requifite to have the good fortune to direft the dif-
courfe from the very beginning towards the way of truth ?
which if any one walk, it will eafily happen, that one fliall meet
with feveral other Propofitions known to be true , either by ^if"
putes or experiments , from the certainty of which the truth of
ours acquireth ftrength and evidence j as it did in every refpe^
happen to me in the prefent Problcme , for being delirous to af'
fure my felf, by fome other accident, whether the reafon ofth^
Propofition, by me found, were true ^ namely, whether the fu^'
fiance of the Magnet were really much leffe continuate than th^^
of Iron or of Steel , 1 made the Artifts that work in the G^IW
of my Lord the Grand Duke , to fmooth one fide of thatpi^^^
of Magnet, which formerly was yours , and then to poli/h an^^
g burnifliit^ upon which to my fatisfaiiion I found what I defir^^'
For 1 difcovered many fpecks of colour different from the i^^^j
but aa fplcndid and bright , as any of the harder fort of Aon^^'^
the reft of the Magnet was polite, but to the taft onely , ii^^
being in the leaft fplendid but rather as if it were fmeered oV^^
with foot 5 and this was the fubftance of the Load-ftone
the fliining part was the fragments of other ftones intct^f^^^
therewith, as was fenfibly made known by prefenting th^^^^^
thereof to filings of Iron , the which in great number le^P^
the Load-ftone , but not fo much as one grain did ftick to the
iaidlpots, which were many , fome as big as the fourth par^
the nail of a mans finger, others fomewhat leiTer , the leaft
all very many, andthofe that were fcarce vifible almoft io^^*^'
merable. So that I did afTure my felf, that my conjeaprc
tru€ , when I firft thought that the fubftance of the Magi^^
was not clofe and compaS , but porous , or to fay better, ff^^"
gy h but with this difference , that whereas the fpongc ^'^
cavities and little eels conteineth Air or Water, the Magnet hath
its pores fhll of hard and heavy ftone , as appears by the
fite luftrc which thofe fpecks receive. Whereupon, as I hav^ ^^^^
«om the beginning , applying thefurface of the Iron to the fu-
P^r^cies of the Magnet the minute particles of the Iron , though
perhapj itorc continuate than thefe of any other body C^^ «^

fliining

Dialogue II L

J'oing more than any other matter doth (liew) do not all nay
"tvery fewof them incounter pure Magnet ; and the contafts
^'ngtew , the union is but weak. But becaufe the cap of the

inv'ct r '.r''^ " P^" fuperficies,

nvefts ,t3 lelf alfo with the virtue of the parts adioynine al-

tZl l^V to-h not , that fide of it beliig exaftlj f.i^.hed
wnich the other face, mhkemanner well poliflit of the Iron to
e attraSed, is applyed, the contraa is made by innumera-
'e minute particles , if not haply by the infinite points of both

TW ur ' ^^'^"^"Pon the union becomcth very ftrong.

inisoblervation of fmoothing the furfaces of the Irons that arc
touch, came not into the thoughts of Gilbert , for he makes
' irons convex, lo that their contaaisvery fmall ; and therc-
Pon It Cometh to paffe that the tenacity, wherewith thofe Irons

^onjoyn, is much leifcr.

thifrt T' ^ T * ^^^""'^ ' ""'^ '^^^ f«i«fied with

'Hsreafon , that if it were a pure Geometrical Demonftration ;
-no becaule we fpeak of a Phyfical Problem , 1 believe that alfo
^"tplicifts Will findhimfclf fatisfiedas far as natural feience ad-
Hits, in which he knows that Geometrical evidence is not to be
required.

Simp. I think indeed that with a finecircflmlo-

cution hath fo mamfeftly difplayed the caufc of this efFed Zt

Zlu fuT I ""^ Sciences , may ap.

prchend the fame, but we confining our felves to the terms of

w4h f fru"* " ^ "g'"'^'"" and mutual appetite

Whlh ' '"''^'^''^ °" '''•^ ''^tred & ennjity for

"icn other things fliun & abhor one another we call Antipathy.
^ GR. And thus withthefe two words men come to render
^^afons of a great number of accidents and cfFeds which we fee
ot without admiration to be produced in nature. But this kind
Philofrphating feems to me to have great fympathy with a
^ "^ain way of Painting that a Friend of mine ufed , who writ
tab • ^'^^ °^ CanvafTe in chalk, here I will have the Foun-
corn^ t*' P'""" ^^"^ Nimphs , there certain Hariers , in this
ftall b ^'^^ * Huntf-man with the Head of a Stag, the reft
thep •^^^"^S) Woods, and Hills; and left the remainder for
himfeTf T Colours ; and thus he perfwaded

contrlbut i ^'^^ painted the Story of ABeon , when as he had
Butwhetlte nothing of his own more than the names,

to our fo ^ wandrcd with folong a digreffion , Contrary

^as that ^1? 'J^'"'""""' ^ ' havealmoft forgot what the poinc
Were upon when We fdl into this magnetick dif-

coarfe-

Sympathy
Antipathy, termi
ufed bj Philofi-
fherstegivtdrea"

fonidfilj of mj-

MmpUdecldrtttgthc

ifiva'tditjf of fomi

PhylofofhtCAl dr-

lumtntfttionu

374

G. G A L I L /E u s, hii Syjlcme.

courfc ^ and yet I had fomething in my mind that I intended t6
have fpokcn upon that fubjefl:.

S A L V. We were about to demonftratc that third motion a-
fcribcd by Cofernicu^ to the Earth to be no motion but a qwie^
fcence and maintaining of it felf immutably direSed with its de-
terminate parts towards the fame & determinate parts of the Uii*'
verfc 5 that is a perpetual confervatlon of the Axis of its diurnal
^revolution parallel to it felf, and looking towards fuch andluch
fixed ftars^ which moll conftant pofition we faid did naturally
agree with every librated body fufpendcd in a fluid and yielding
medium , which although carried about, yet did it not change di-
reftionin rcfpefl: of things externaljbut onely feemed to revolve in
its felf, in rcfpeft of that which carryed it round , and to the
velfel in which it was tranfported. And then we added to this
fimple and natural accident the magnetick virtue , whereby the
felf Terreftrial Globe might fo much the more conftantly keep
immutable,

S A G R. Now I remember the v^hole bufinelTe ^ and that which
then came into my mindc,& which I would have intimated, wa^ ^
certain confideration touching the fcruple and ob)e£i:ion of Si*^^'
flicitis^ which he propounded againft the mobility of the Eaitl^>
Theftverai tt4' taken from the multiplicity of motions, impoffible to be afligne^
llT^Jf^Z *^ a fimple body, of which but one fole and fimple motion,

cording to the doftrine of Anjiotkj can be natural^ and tb^
which 1 would have propofed to confideration, was the Magnet)
to which we manifeftly fee three motions naturally to agree -
one tow^ards the centre of the Earth, as a Graifc j the fecond
the circular Horizontal Motion , whereby it reftores and coH'
fervcs its Axis towards determinate parts of the Univerfe ;
the third is this, newly difcovered by Gilbert^ of inclining J^*
Axis, being in the plane of a Meridian towards the furface of
Earth, and this more and lelTe, according as it (hall be dift*^^^.
from the Equinoftial, under which it is parallel to the Axis oi
the Earth. Bcfides thefe three, it is not perhaps improbable?
bill that it may have a fourth, of revolving upon its own Axis
cafe it were librated and fufpended in the air or other fluid an^J
yielding Medium^ fo that all external and accidental impeditt^ent^
were removed, and this opinion Gilbert himfelf feemeth alfp
applaud. SothzU Simplicifis^ you fee how tottering the A^^^^^
of Arijiotlc is.

S I M p. This doth uot only not make againft the Maxi^^'
^ot fo much as look towards it : for that he fpeaketh of a fi^P
^^^Yy and of that which may naturally confift therewith ?
you propofe that which befalleth a mixt body ^ nor do you
us of any thing that is new to the doarinc of Jnjtotle, (ot tha^

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

A L O G U E

III.

fc'clikeWife granteth to mixt bodies compound morions by

^ S A G n.Stay a little,- Stmpliciu^^ & anfwer me to the queftions
' ftall ask you. You lay tnat the Load-ftone is no fimple body,, -
^owldefire you to tell me what thofe fimple ]>odies are j> Jtliij^
"tingle in compofing the Load-ftone. ' ' '^-i^ /i; ;!j -jti. ,

S I M I know not how to tell you th'tngtiedients nor finiples
precifely^- but it fufficeth that they are things elementary.

k L V. So much fufficeth me alfo. And of thefe fimple elq-
"^ntary bodies, wh^tt are the natural motions ?

Simp. They are the two Tight a^d fimple motioris^ ifurfum.
^nd deorfnm} "-'^^ ^^"^^ c^^^^**' ri'Jidw ^Lc<i iLth oz bAL ^oL iitiD ry:
S a gr. Tell i^eWtHe heHtffaie^^ Do the
"lotion, that fhall remain natural to that fame mixed body, fliould
°^ one that may refult from the compofition of the two fimple
^^tural motions of the fimple bodies compounding , or thaf it
^ay bea motion impoffible to be compoicd of them, - )

S I M p. I believe thit it ftiall move with the motion rcfu/ting
from the compofition of the motions of the> fimple bodie«.coni>»
poundingi f^^^ with a motion impofliblc to be compofcd-of
^hefe,itisimpofliblethatitfliouldmove. ' ^ j / •

S A G R. But56/wr;>//V//^5witb two right and4%nple motions^yoii
fliall never be able to compofe a citcu^far motion , filch fcid are the
two, or three circular motions that the magnet hath: you fee
^hen into what abfurditics evil grounded Prinqiples , or , to fay
l^etter, the ill-inferred confequences of good Principles Onriy^ a
iiian i for you are now forced to fay , that the Magnet is a mix-
tu.re compounded of fubftancesjelementary and'coeleflfal, if you
will maintain that the ftraight motion is a peculiar to fhe Ele-
^ents^ and the circular to the<:oeleftial bodies. Therefore if
ybu will more fafely argue 5 you muft fay, that of the integral
'^^idies of the Univerfe, thofc that are by nature moveable, do all
^^Ve circularly, and that therefore the Magnet, as a part of the
primary, a^id integral fubftattce of our Globe, pertakethof
fame qualities with it. And take notice of this your fallacy^
J? ^ailing the Magnet a mixt body , and the Terreftrial Olobe a
""^Webody, which is fenfibly petc^ved to be a thoufand times
compound : for, befides that it containeth an hundred an
"i^ndrcd matters, exceeding different from one another, itcon^
J^^^^h great abundance of this which you call mixt , I mean
9^ Load-ftone. This feems to me juft as if one fliould call
bread a mixt body, and " Pannada a fimple body, in which there
put no fi^^^j, quantity of bread, befides many other things edl-
This fcemcth to me a very adtaiirable thingjamongft others

Umixt hoiies»

mixt hodi's ottfrht
to fuch 4Bt may
nfult from the
C9mpo(tvon of tU
moticmf of the Cm-
fie Mi€t corn-
founding.

With two right
motions one CMnmt
comfoft cirsuUr
motionr,

Pbilofofhers Mte
forced to confeffc
thdt the Magmt
U compounded of
calefiiMl fu^fiM'
ceS'i Andof iUmtrf

tMTJ,

The irrottf
thofe wb9 CdUjBe
UHagnet a mixt
body^ dndtheter^
refiridl Gloh 4
fimlrlehodj.

* Ogliopocrid*
k Sfauifh dijh of
munj ingrcMinfi
btUdttgttbtr^

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

5^^. G. G A L 1 L us y his %peme.

The Vifcouyfes of the Peiipatcticks:, who grant (BO^cai^k^ed
of perifMtenckh Terrcftrial Globc IS, ^/e faiio-:^ ar€oiTipc)-wrid_of :uifiJ^ite.ditt^^^
imf/^aZr.''''^ matters j and grant farther th^t of compoui>4 bodics.the* motipn{
««M / tn, Q^gj^j. JO be compound : now tb^.motion? ih^t admit .of co^^

fition are the right and circular i -For thp rigli^; Wl^cions, 4^:
being contrary, are incompatiblei^pgeth^fjo; jhcy aftifjp, that tlie
pure Elcment.of Earth is, no where, to^be fpxiud , they confcfi^ij
that it never hath ibeea moved withra lo€^i fflqiioa, .apd ye^ rhey
will introduce in Nature tha t body which is fwt (o b9;^9und,
make tt^ move with that motion .wJiuf:h it fiever exertifqdj nor P^"
ver (hall do, and to that body which hath, and ever h^ a being?
they deny thatmption, whiab^tetpi^e^ jficy.§ii?iited,.,9ught
rally to agree therewith^ . rh oj j;..-. rii; t": - r?7 -rjtoffi

- f^vNi ib^kcch you^ Sagredus^ let us mt weary cur fely^^^'
anymore about theie particiiUtSvand. the^r^tjier,,
know that our purppfc was not fto determii^c leiqlutel^, or .^^b
accept for true, this or that opinion, buq p^^^y to prppsolc for
divcrtifement fuch reafons, and ^nfwers a^cqiay be ^aUe^dged on
the one fide, or on the other and Si^phcius maketh this aft-j
fwer, in defence of his Peripate ticks, therefore let us ieave t^^'
judgment in fufpehfe, and repait the dqterminatiop into
hands of fuch as are more k^ipwnthau^y^^^^
that we have, with fuflBcient prpH3city> !in ,thefc three dfty^^?
courfed upon the Syfteme of the Univerfc,, it will npw b^e fcW*
nabl4rthat we proceed to the grand accidc^it, from whence
Difputations took beginnings 1 mean, of the ebbing and fl^vvilig
of the Sea, the caofe whereof may, in all probability, be, refeffCj|
to tlie motion of the. Earth. But that, if you fo pleafe, we
referV:e till to morrow. In the mean time^ that 1 may not
it, I will fpeak to one particular, to which I could have wi^^^'
t\\dit Gilbert had not lent an car ^ I mean that of admitting? ^^^^
bU^eEt ^admired in cafe a little Sphere of Loadftone might be exaftly librated> ||
h ^{\hcrzMsi» the ^ould xevolve in it fclf j bccaufe there is no reafon why it fto^
£^adfio^. do fo ^ . For if the whole Terreftiial Globe hath a natural ft^^J
ty of revolving about its own centre in twenty four hours,
that all its parts ought to have the fame, I mean, that faculty
turning round together with their tphole^ about its centre in tv^?^
ty four hours they already have the fame in effefi:, whilft ^^^^^
being upon the Earth, they turn round along with it: A^^
affigning them a revolution about their particular centres,
be to afcribe unto them a fecond motion much different ff^^
firft: for fo they would have two, namely, the revolving in tv^f '
four hours about the ccntr^i of their whole -, and th^ ^^^^^^
about their own : now this fecond is arbitrary, nor is there ^^J^

I A LOGU E

III.

577

eafon for the introducing of it : If by plucking away !f 'pete

of Lo

depr

The vain srgtt*
mentation of fimi
to prove the Eie»

^adftone from the whok natural malle, it Were
the faculty of following it, as it didV wh'tlft itAvas united t!?^flreto,
^0 that it is thereby deprived of the rcvokitit6njab6fcft tlfc univer-
^il centre of the Terreftrial Globe, it might-' tfaply, with fome-
what greater probability be thought by fome, that the faid Mag-
was to appropriate to it felf a new converlion about its parti-
cular centre j but if it do noleffe, when feparated, than when
conjoyned, continue always to purfue its firft, eternal, and natu-
|"al courfe, to what purpoie (hould we go about to obtrude upon
Jt another new one ?

^ A G 1 underftand you Very well, and this puts me in mind
a Difcouifc very like to this tor the vanity of it, falling from
^^rtain Writers upon the Sphere , and I think, if I well rcnjcm-

amongft others from Sacrobofco^ who, to (hew how the E- mint of water to
dement of Water, doth, together with the|arth, make a com- of s spherical
pleat Spherical F igure, and to between the^ both compofe this
^tir Globe, writeth, that the feeing the fmajt * particles of water
ftspe themfelves into rotundity, as in the ilrops, and in the dew
daily apparent upon the leaves of fe>^ral herbs, is a ftrong ar-
gument, andbecaufe, aejCording tp 'the trite Axiome, there is
the fame reafon for the whqle, 0J^ the parts, the parts afFeSing
that fame figure, it is neceffary^at the fame is proper to the
Whole Element : and truth is , methinks it is a great overfight
that thele men (hould not perceive fo apparent a vanity, and con-
fider that if their argument had run right, it would have follow-
^d, that not only the fmall drops,but that any whatfoever greater
quantity of water feparated from the wholeElement, (hould be re-
duced into a Globe: Which is not feen to happen^ though indeed
tneSenfesmay fee, and the Underftanding perceive that the E-
*^uient of Water loving to form it felf into a Spherical Figure
^l^out the common centre of gravity , to wkich all grave ho-^
^ies tend ( that is , the centre of the Terreftrial Globe ) it
therein is followed by all its parts , according to the Axiome 5
^that all the furfaces of Seas, Lakes, Pools, and in a word,
^11 the parts of Waters conteined in vcffcls , diftend
^uemfelves into a Spherical Figure , but that Figure is an arch
n^!^^^ Sphere that hath for its centre the centre of the Ter-
];cjtrial Globe , and do not make particular Spheres of them-
lelves.

, S ^ L v. jhe errour indeed is childifll ; and if it had
/^^n onely the fingle miftake of Sacrobofco , I would ea(ily
allowed him ia it j but to pardon it alfo to his Com-
'^ntatorsj and to other famows men , and even to Ptolomy

B b b

G. tj A L I L ^ u s, his Syflcme.

himfelfc, this I cannot do v without bliilhing for their repu'
tatibn. But it is high time to take leave , it row being
very late , and we being to meet again to morrow^
at the ufualhour, to bring all the foregoing
EMfcourfcs to a final conclufion.

BIBIJOTHECA

yNiVERSITATlS

379

G A L I L iE U S

Gaikus Lyncajus,

SYSTEME

O F T H E

VVORLD.

The Fourth Dialogue.

wtEKL^cvroKs.

SaLVIATUS.SaGR-EDUS, & SiMPLlCIUS.

know not whether your return to out
accuftomed conferences hath really been
later thanufual, or whether thedefirc
of hearing the thoughts of SdmttHS^
touching a matter fo curious , hath
made me think it fo : But I have tar-
ried a long hour at this^i«f "P;-
aing every moment when the GondaU
would appear that Kent to fetch you.

,ly believe that your imaginatfon more than our
:yrn.ed the time: and tomakenolonge de

L V. I veri._, -

tarriancc hath prolonged the time : a"" '^"f^"'''Z"'/"'^L ^. N*titre»ffrt
"'^irre it would be well, if without mterpofing more words, we
came oimatteritrclf. and did fhew, that nature hath per- WJ;^^/;*;.
•fitted Cwhrtherthcbuanefs/« ^.«f<.re be fo, or elfe tQ play '^::;:,,Zmr..
^ B b b 2 and

§So t3. G A L I L ^ u hh Syflcmc.

le a»d ^J^d fpo^t with our Fancies) hath, I fay, hath permitted that the
If 7he niotions*r Wery 6f|isr refped, |Kcep%to rcfoWe thc^bbin^.and

fming f^^^^^^^^*^^ long Once t| the eaj^fhoa^^ be ((^^4
now at lalT to anfwer exaftly tothe'^cauf<?tTOreof*5 and, ^^^^

7 he tide^ and

Earth mutually
confirm e^ch other

^AU terrene ef' wcfc, with -mutual a emulation ^ the faid , ebbing and flowing
fcBs indifferemij appear in confirmation of the TcrreftriaL'motion : the jndice^

eo» firm the mot to» Jtr in-i i z^na

cr reft of the whercoi have hitherto bccu takcn from the coeleliial Phaenomeiwj

Earth, except the jn regard that of thofe things<tli4t bippen on Earth, not any one

ebbing and fiomffg c • • l l, . urp al-

cfthisea, vnfiB o^'forc||to glove ^iniopfla^e.thai^^oth^ rjSS

^ fhewiiig that alt^^e tehcne

rcaUyfta vc » l^^t provc^^^w fhe wii|| I , _

^^^y P^^^^ the ^abigty of tl£ Earth'and mobility of the
Sun anh Firmament is commbiily inTerred, are to Teem "to us pe>^'
formed in the fame manner, ; ih(High|Wp Juppofed the mobility
the Earth, and the immobiiii^ of themf The Element of VV^'
tcr oneiy, as being m^l: vaftf^aiS^ whitli is iH^t annexeS an3 con-
catcna^d to the Terr^rial as all us ipther folid parts are?

yeav fitjber which by ^reafon of its fluidicy. femaineth ig)arc /^^
jurisy ancTfiec, is to be ranked aiiiongfl: tliofe fublunary things*
from which we may colled fome hinte and intimation of what the
Earth doth in relation to motion and reft. After I had niany
aod many a time examined with iity felf the cfFefts and accidents,
partly fecn and partly underftood from others, thar are tO be oD-
fervedin themocions of waters : and moreover read and he^^^
the great vanities produced by «Hi«y, as the caufes of tJiofe acci-
The firjt ene^ ^^^nts, I have been induced upon no flight reafons to omit thel^
ymI conciufkTof two conclufions CWviiig made wrthal the necefTary prefupp^'
theimpofflhility of^ f^Js) that in cafe the terreftrial Globe be immoveable , the flii^
fl^hg^lliimZ- arid tcfliix of the Sea cannot be natural; and that, in cafe thofe
tiiityrf the terre- motions bc Conferred upou the faid Globe, which have been lon^
gri'^lcT^' ^"''^ finceaflignedtoit, itisneceffary that the Sea be fubjeft t^^^"
bing and flowing, according to all that which we obferve to hap-
ftHifrthefeine.

S'Afc'i/'The f^^ is very confiderable , as well for
ftlF^^ fiiir' vdhatfonoweth upon the fame by way of confequ^"^^'
ip ty^ i'fhaH the more intcnfly hearken to the explanation and
tonfirmatitki of it.

The kKowiedge S A I'v. Bcca life in natural qucftions , of which number tb/s
t!tft^\trL wliich weiiav^in hamiisone, the knowledge of theeffeasi^^
vel^iiaiunof^xhi mcaus to gt^id^ US to thc invcftigation and difcovcry of the
cAHfes, f^g: ^nd; Without yhich we fliould walk in the dark, nay

moreuncertainty, for that we know not whither we would g^'
whereas thfc blind,at lcaft5know where they defire to arrive, tbefe-
fore fii ft of all it is necefl^ary to know the effcSs whereof
quive^tht caufes: of which effefts you, S^^rerf^d", ought Uior^
abundiiittly and more certainly to be informed than I

Dl A LOGUfi. 1 V. .

asone, that befides your being bornj and havimg, for a long
time, dwelt in Venice^ where the Tides are very notable for their
greatneffc, have alio failed into Syria ^ and, as an ingenuous and
^Pprehenfive wit, muft needs have made many Obiervations up-
on thi8.lub jeft : whereas I, that could oncly for a time, and that
^^ry fliort^ obfervc what happened in thefe extr^atn parts x>t the
^driaticl^ Qxx\^\\^ and in our Seas below about the Tyrrhene
fliores, muft needs take many things upon the relationi of o-
thers, who, for the moft part, not very well agreeing, and con-
^^quently being very uncercaia, contribute more of confufion
than.contirmation to our fpcculations. NeverthekfTc, from thofc
that we arefureof, atid which arc the principal, I think l am a-

to attain to the true and primary cauies ^ notthar>l pr^t^nd
to be able to produce all the proper and adequate rcafons of
thofe effefts that are new unto me, and which confequently I
Could never have thought upon. And that which 1 have to fay,
I propofe only, as a key that openeth the dood to a path ntver
y^t trodden by any, in certain hope, that feme wits morefpecu-
lative than mine, will make a further progrefle Herin, and pene-
trate much farther than I lhall have done in thi& my firft L>ifco-
^^ry : And although that in other Seas,remote from us, there may
happen feveral accidents, which do not happen in our Mediter-
ranean Sea, yet doth not this invalidate the reafon and caufe that
Ifliall produce, if fo be that it verifie and fully refolvc the ac-
cidents which evene in our Sea : for.that in conclufion there can
'^ebut one true and primary caufc of theeffcfts that are of the
fame kind. I will relate unto yod;,' - therefore, the efFefis that I
know to be true , and afligne the caufes thereof that I think
to be true, and you alio , Gentlemen , fliall produce fuch
others a? are known to you^ befidcs mine, and then we wiil

whether the caufe , by me alledged, may fatisfie them

^Ifo. Three 'Pericdi

1 therefore affirm the periods that are obferVed in the fluxes fj^^^XurZt
refluxes of the Sea- waters to be three : the firfl and princi- mo»ethi;, and an-^
P^l is this great and moft obvious one^ namely ,the diurnal,accor-
^^iig to which the intervals of fome hours with the waters flow and
, ; and thefe interval are, for the moft part, in the Mediter-
^^ne from fix hours to fix hours, or thereabouts, that is, they for
fi^ hours flow, and for fix hours ebbe. The fecond period is
"^onethly, and it feemes to take its origen from the motion of
^he Moon, not that it introduceth other motions , but only al-
^ereth the greatneffe of thofe before mentioned, with a notable
^'fference, according as it (hall wax or wane, or come to the
Jiyadrature with the Sun. The third Period is annual, and is
feen to depend on the Sunne, ahd onely aikereth the diurndl

mdtians^

G. G A L 1 L A u s , hu Sjfletne.

inotionSj hy making them diftcrent in the tifnes of the Sol*
ftices, as to greatnefl'e, from what they are in the Equinoxes.

We will lpeak(in the firft place, of the diurnal motion,
being the principal and upon which the Moon and Sun fcem to
rMriettis that ^^^^^^f^ ^^^^^ powcr fecondarily, in their monethly and annual
happen in thedinr- alterations. Three differences are obfervable in thefe horary
nalfemd. mutations ^ for in fome places the waters rife and fall, without
making any progreflive motion , in others, without rifing or ftl*
ling they run one while towards the Eaft, and recur another
while towards the Weft i and in others they vary the heights
and courie alfo, as happeneth here in Venice^ where the Tides ii^
coming in rile, and in going out fall , and this they do in the cX-
tcrmities of the lengths of Gulphs that diftend from Weft to
Eaft, and terminate in open ftiores, up along which (horcs the
Tide at time of flood hath room to extend it felf : but if the
courfe of the Tide were intercepted by Cliftes and Banks of
great height and fteepnefle, there it will flow and ebbe without
any progfvffive motion. Again, it runs to and again, without

* A Strait, fo changing height in the middle parts of the Mcditerrane, asnota-
calkJ. bly happeneth in the * Faro de Mcjpajj between Scylla and 6>

ryhdfSy where the Currents, by reafon of the narrowneffe of
the Channel, are very fwift j but in the more open Seas, and
about the Ifles that ftand farther into the Mcditerjanean Sea, as

* Or ilvt. (jjg BaleareSyCorfica^Sardigniay" tlba^Sicily towards the Jffricaf^

* Or;Crcta. Coafts, Malta^ * Candia^ id^c. the changes of watermark ar^

very fmall ^ but the currents indeed arc very notable, and efp^'
cially when the Sea is pent between Ifland?) or between theO^
and the Continent.

Now thefe onely true and certain cffefts, were there no mofc
to be obferved, do, in my judgment, very probably perfwade
any man, that will contain himfeif within the bounds of natu-
ral caufes, to grant the mobility of the Earth : for to make the
vefTel (as ic may be called) of the Mediterrane ftand ftill> and to
make the water contained therein to do, as it doth, exceeds m/
imagination, and perhaps every mans el fe, who will but pierce
beyond the rinde in thefe kind of inquiries.

Si MP. ThefeaccidentSj^rf/^/tf/;^, begin not now, they arc
moft ancient, and have been obferved by very many, and fevcra*
have attempted to affigne, fome one, fome another caufe for the
fame: and there dwelleth not many miles^from hence a famous
rhecaPff^cf the Peripatctick, that alledgeth a caufe for the fame newly fi(hcd out
,ybirffdndflown^ of a ccrtaiu Text of Ariftotle ^ not well underftood by his
tf^t^nFbi^ Poflcors, from which Text hecollefieth, that the true caufe ot
Tofifhtr. ^^^^^ motions doth only proceed from the different profundities

of Seas : for (i^at the waters of greateft depth being greater m

abun-

I A L O G U E.

IV.

383

^^undance , and therefore mare grave , drive back the Waters
Icffe dcpch , which being afterwards raifcd , deiire to de-
and from this continual colluclation or conteft proceeds
^he ebbing and flowing. Again thofe that referrc the fame to the

oon are many , faying that (he hath particular Dominion over

the Water , .and at laft a certain Prelate hath publilhed a little
Treatife ^ wherein he faith that tlie Moon wandering too and
ftoin the Heavens attrafteth and draweth towards it a Mafleof
^^tcr, which gocth continually following .it, fo that it is full Sea
^Jwayes in that part which lyeth under the Moon *, and becaufej
^hat though fhe be under the Horizon , >et neverrhelelTe the Tide
retprncih, he faith that no more can be faidfor the falving of that
Particular, favc onely, that the Moon doth not onely naturally
^^tain this faculty in her (elf ^ but in this cafe hath poWerto con-
it upon that dee;rec of the* Zodiack that is oppofite unt6 it.
Others . as I believe you know , do fay that the Moon is able
^'ith her temperate heat to rarefie the Water , which being ra-
fefied, dot-h thereupon flow. Nor hath there been wanting Tome
that — ^ • :..

Sa GR, I pray yosiSimplicius let us hear iio mare of therii,
for I do not think it is worth the while to waft time in relating
^hcm , or to ipend our breath in confuting them , and for your
Part , if you gave your afTent to any of thcfe or the like foole-
ries , you did a great injury to your judgment , which ncverthe-
'^(Te I acknowledg to be very piercing.

S A L v. But I that am a little more flegmatick than you, Sagri-^
dm ^ will fpend a few words in favour of SimpliciffS ^ if haply
j^^ thltvks that any probability is to be found in thofe things that
hath related. I fay therefore : The Waters, Simplkius^ that
nave their exteriour fuperhcies higher, repel thofe thap arc infe-
^iour to them , and lower 5 but fo do not thofe Waters that are
^ grcatcft profundity ; and the higher having once drirenback
^'^^ lower, they in a (hort time grow quiet and*lcvd. This
ypur Periparctic\ muft needs be of an opinion, that all the Lakes
the World that are in acalme , and that all the Seas where
Jl^ebbing and flowing is infenfible , are level in their bottoms^
I v^as fo fimple , that I perfwadcd my felf that had we no o-^
Plummet to found with, the Ifles that advance fo high a-
^ve Water , had been a fufficient evidence of the unevcnneffc
^heir bottomcs. To that Prelate I could fay that the Moon
^neth every diy along the whole Mediterrane , and yet its
J^^t^rsdo not rife thereupon , fave onely in the very extreani
T^^t^ds of it Eaftward , and here to us kt Venice. And for thofe
^hat make the Moons temperate heat able to make the Watet
Iwell J bid them put fire under a Kettle full of Water , and hold

thek

The catife of
the ehhifig Mfid
fioiving afcribed to
the fJMoon a
certain VreUte,

Hieronymus Bor-
rius Mttd other Pc-
ripaccticks refer it
to the temfernte
heat of the Moon\

iAnftvers the
vanities nUedged
/u C4ufes of the eB-
bing and flowing.

+ Or rathci
fmooth.

The \jles dre to-
h»s of the une^
ve»t,ejfe of the
bettomts of Seis*

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

384

Toetick^ wits of
two kj»tiS'

Truth haih fret
fi little l/jfh da
not to he Aifcover-
edamidfi theum^
brdges of fM-

Arifco le hUttb
ihofe cffells to he
mirdcttloiu , of
vfhtch the Cdufts
Mre uul^wwft*

G. G A L 1 L ^ u s J his Syjieme.

their right hand therein till that the Water by reafon of the heat
do rile but one fole inch , and then let them take it out , and
Write off* the tumefaftion of the Sea. Or atleaft defirethemrc>
fliewyou how the Moon doth to rarefie a certain part of the
Waters y and not the remainder , as for inftance, thcfehere 01
Venice^ arid not thofe of Ancona^ Naples^ Gf/?(7'^^ ; the truth is
Poetick Wits are of two kinds y fome are ready and apt to
invent Fables, and others difpofed and inclined to believe them*

Simp, I believe that no man believeth Fables , fo long he
knows them to be fo j and of the opinions concerning the caufcs
of ebbing and flowing y .which anczi many , becaufe 1 know thato*
one fii gle cfFcft there is but one fingle caufe that is true and p^i*
mary, 1 undcrliand very well, and am certain that but onealou?
at the mpfi can be triie, and for all the reft I am fure that tliey
fabulous, and falfe v and its poffiblc that the true one may not h^
among thoi'c that have been lutherto produced , nay I verily
lieve that it is not , for it would be very ftrange that the truth
ftould have fo little light, as that it (hould liot be vifible among^
the umbrages of fo many falflioods. But this I fliall fay with the
liberty that is permitted amongft us , that the introduflion of the
Earths motion, aiid.the making it the caufe of the ebbing
flowingiof > Tides , feemeth to me: as yet a conjefiure naleffe i*"
bulous than the reft of thofe that I have heard j and if tbcr<?
fliould not be propofed to me reafons more conformable to natH'
ral matters, 1 would without any more ado proceed to belie^^
this to bp^ fupernatural efFed, and therefore miraculous, an^l
unfearchable to the underftandings of men, as infinite others th^^^
a^i^^., that immediately depend on the Omnipotent hand of Go^-
S A G R. You argue very prudently , and according to the
Dofirine pf Ariflotley whp you know in the beginning
mechanical queftions referreth thofe things to a Miracle , t*^^
<^aufes whereof are occult. But that the caufe of the ebbing ^no'
Hawing is^ one of thofe that are not to be found out, I believe
you have m greater proof than oncly that you fee , that amongft
all thofe that haye hitherto been produced for true caufes there-
of, there is not one wherewith , working by what artifice yo^
wiU , w^ are,able to reprefent fuch an efFeft 5 in regard that t)Ci^
ther with the light of the Moon nor of the Sun , nor
temperate hrats , nor with different profundities, (hall one ever
artificially make the Water conteined in an immoveable ^^^^^
to run one w^ay or another , and to ebbe and flow in one pl^f^
and not in another. But if without any other artifice , but
the onely moving of the Velfel , 1 am able punftually to r^P^*^'
fent all thofe mutations that arc obferved in the Sea Water 5 ^''^
wiil you f efufe this reafon and nm to a Miracle >

Simp-

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

I ALOGUE.

IV.

585

Sim 1'. I will run to a Miracle ftill, if you do not with fome
"^^^^r natural caulcs, belides that of the motion of the Veffels of
^he Sea- water dilfwade me from it , for I know that thofe V eflels
^ovenot, in reg^ard that all the entire Terrcftrial Globe is natu-
'■^lly immoveable.

^ A L V. But do not you think, that the Terreftrial Globe might
^"pernaturally, that is, by the ablolute power of God» be made
"Moveable > Simp. Who doubts it ?

Lv. Then SimpliciHs^ feeing that to make the flux and
^^flux of the Sea, it is nccelTary to introduce a Miracle, let us
luppofe the Earth to move miraculoufly, upon the motion of
Hich the Sea movcth naturally : and thisefteft fliall be alfo the
"^^rc fimplc^ and I may fay natural, amongft the miraculous o-
rations, in that the making a Globe to move round, of which
^Jnd we fee many others to move, is Icffe difficult than to make
immenfe maffe of water go forwards and backwards, in one
place more fwiftly, and in another IcfTe, and to rife and fall in
lome places more ^ in fome lelTe, and in fome not at all ; and to
^ork all thele different effefts in one and the fame Veffcl that
l^^ntaineth it : befides, that thele are feveral Miracles, and that
but one onely. And here it may be added, that the Miracle
making the water to move is accompanied with another,
timely , the holding of the Earth ftedfaft againft impctuofities
the water , able to make it fwage fometimes one way, and
Sometimes another , if it were not miraculoufly kept to rights.
, S A G R. Good SimpliciHS^ let us for the prefent fufpcnd oar
Judgement about fentencing the new opinion to be vain that Sal^
[ y^^^^ is about to explicate unto us , nor let us fo haftily flyc out
pairion like the fcolding overgrown Haggs : and as for the
Vliracle, we may as well rccurre to it when we have done hca-
Il'^gthcDifcourfes contained w ithin the bounds of natural cau-
though to fpeak freely, all the Works of nature, or rather
^^God, are in my judgement miraculous.
J ^ A L V. And I am of the fame opinion 5 nor doth my faying,
^^tthp of the Earth is the Natural caufe of the ebbing

motion

flowing, hinder, but that the faid motion of the Earth may
^ "^'^raculous. Nowreafluming our Argument, I apply, and
^gain affirm that it hath been hitherto unknown how it
^'gHt be that the Waters contained in our Mediterranean
,7^^§hts (hould make thofe motions , as we fee it doth if fo b^
Z Straight, or containing \ effel were immoveable.^ And
, ^hich makes the difficulty , and rendreth this matter inextri-
^^^^^ arc the things which I am about to fpeak ot , and which
daily obfcrved. Therefore lend me your attention.

are here in Venice^ where at this time the Waters are lowr,

Ccg the

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

386

■It U proved
imyjfihle that
there (Jjonid tiatu-
rsllf he any ehhtn^
And, Rowing , the
'Earth being im-
moveable,

* Palms,

+ Liff^is a fait
Port ia the Vene-
tian Gulph , lying
N. E. from the
City, .

G. G A L I L u s 3 his Syfleme.

the Sea calm, the Air tranquil ^ fiippc^e it to be young flood,
and that in the term of five or fix hours the water do rile

hand breadths and more , that rile is not made by the fi"
water, which was faid to be rarefied, but it is done by theacccl-
fionof new Water: Water of the fame fort with the former,
of the fame bracklflinefs, of the fame denfity, of the fam^
weight: Ship?, S/w/^/zcz/^, float therein as in the former, with-
out drawing an hairs breadth more water y a Barrel of this fecond
doth not weigh one fingle grain more or lefs thanfuch another
quantity of the other, and retaineth the fame coldncfs without
the leaft alteration : And it is, in a word, Water newly and vifi-
bly entred by the Channels and Mouth of the * Lio, Confidef
now, how and from whence it came thither. Are theie happ'y
hereabouts any Gulphs or Whirle pools in the bottom of ih^
Sea , by whi^h the Earth drinketh in and fpuetli out the Water?
breathing as it were a great- and monftruou? VV hale ? But if tb'^
be fo, how comes it that the Water doth not flow in the fpace of
fix hours in Ancona^ in * Kagufa^ ia Corfny wliere the Tide is ve-
ry fmall, and happly unobfcrvable > Who will invent a way to
pour new Water into an immoveable VefTd , and to make that
it rife onely in one determinate part of it , and in other places
not ? Will you fay, that this new Water is borrowed from the
Ocean, being brought in by the Straight of Gibraltar ? Th*^
will not remove the doubt aforcfaid , but will beget a greater-
And firft tell me what ought to be the current of that Water?
that entering at the Straights mouth, is carried in lix hours
theremoteft Creeks of the Mediterrane , at a diftance of tW^
or three thoufand Miles, and that returneth the fame fpace ag-ai^^
in a like time at its going back ? What would Ships do that lye out
at Sea? What would become of thofe that fhould be in the
Straights-mouth in a continual precipice of a vaft accumulation o.
Waters, that entering in at a Channel but eight Mile broad, is to
give admittance to fo much Water as in fix hours ove:'floweth a
traa of many hundred Miles broad,& thoufands in length? VVh^^
Tygre , what Falcon runneth or flyeth with fo much fwiftnefs ?
With the fwifinefs, I fay, of above 400 Miles an hour. The cut'
rents run (nor can it be denied) the long-wayes of theGulph;^^^^
fo flowly , as that a Boat with Oars will oui -go them, thoug''
.deed not without defalking for their wanderings. Moreoverjii ^ his
Water come in at the Straight , the other doubt yet reniainefh?
namely,how it cometh to flow here fo liigh in a place fo remote?
without firft rifing a like or greater height in the parts more adj^"
t ? Ia a word,! cannot think that either obftinacy,or fliarpnei^
of wit can ever find an anfwer to thefc Objedions , nor confe-
qucntly to maintain the ftability of the Earth agaihft them, keep-
ing within the bounds of Nat-ure. S a g

Dialogue.

iV.

A G R. I have all the while perfeflly apprehended youin this*,
^"d I liand greedily attending to hear in what manner thefe won-
ders may occur without obftruftion from the, motion already af-
figncd to the Earth.

S ^ L V, Thcfe effefts being to cnfue in confequcnce of the mo-
tions that naturally agree with the Earth, it is neceffary that they
not onely meet with no impediment or obftacle,bat that they do
follbw eafily, & not onely that they follow with facility ^but with
ntceQIty^fo as that it isimpoflible that it fhould fucceed otherwife^
^or fuch is the property & condition of things natural & true. Ha-
ving therefore (hewen the impoffibility of rendring a reafon of the
"motions difccrned in the Waters, & at the fajrte time to maintain
^l^e immobility of the velfcl that containeth themiwe may proceed
enquire, whether the mobility of the Container may produce
theiequircd elfeft, in the manner that it is obferved to evene*

Two kinds of motions may be conferred upon a Vcffel, where-
'^y the Water therein contained , may acquire a faculty of flu-
^"ating in it, one while towards one lide , and another while
^^vvardo another ^ ^^^^^ while to ebbe, and another

^v^hilc to flow. The firft is^ when firft one, and then another of
^hofe ildes is declined, for then the Water running towards the
'ncHning fide , will alternately be higher and lower , fometimes
On one fide,and fometimes on another. But becaufe that this rifing
^nd abating is no other than a recelTion and acceflion to the centre
of the Earth, fuch a motion cannot be afcribed to the concavi-
ties of the laid Earth, that are the Veffels which contain the Wa-
tiCTs ^ the parts of which V effel cannot by any whatfoever motion
^fllgned to the Earth , be made to approach or recede from the
^^ntre of the fame The- other fort of motion is , when the
^effel moveth (without inclining in the Jeaft) with a progreffive
Motion, not uniform, but that changeth velocity, by fometimes
^^<^ellerating, and other times retarding : from which difparity
Would follow, that the Water contained in the VefTel its true,
J^^t not fixed faft to it^ as its other folid parts, but by reafon of
fluidity , a^-if it were feparated and at liberty , andnotbbli-
to follow all the mutations of its Containeri,in the retardation
^f theVeffel, it keeping part of the impetusheforc conceived^
^ould run towards the the preceding part , whereupon it ^6uld
nccefliry come to rife h and on the contrary, if new velocity
J^uldbeadded totheVeifel, with retaining ?>aTts of itstardity,
% ing foiiiewhat bellinds before it tould habituate it felf to the
"^'wpef«^, it would hang back towards the followmg part ,
^^^^^ it would come to rife fomething. The which effefts we
plainly declare and make out to the Senfe bjr the exarilple of
of tiiofe fame Bark& yonder, which coiumually Gome/ifr<^

C c c S ! Li%%a^

True andnatH-
rvithom difficftltjt.

Two fortt of
mot torn of the con-
taiKtHg V'effel^may
i^*ks the ccntM»
'ted vfater to rift
andfdll.

theCdvities of
the Earth cAnnet
approach or go far*
t her from tbecen*
treophefamc

The f>r9grfive
and uneven motion
may make the wa-^
ter contained '» 4
f^effel to run tt
dndfro.

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

588

+ K Town ly-
in^S.E.of

fhe parts of t'^e
ttrrefinal Globe
itccelerate and r*-
$4rdinthiirmoti'

G. G A L i^L ^ u s y his Syjleme.

Li'x*%a'Fufn!a^hden with frcfti water^for the fervice of the O^Y'
Let us therefore fancy one of thofe Barks, to come from thcn^^
with moderate velocity along the Lakc,carrying the water gcntJy?
of which it is full : and then either by running a ground, or
fome other impediment that it fhall meet with, Jet it be notably
retarded. The water therein contained (hall not, by that means,
lofe, as the Bark doth, its pre-conceived impdm^ but retaining
the fame, ftiall run forwards towards the prow, where it fli^'^
rife notably, falling as much a ftern. But if, on the contraryj
the faid Bark, in the midft of its fmooth courfe, fliall have a new
velocity, with notable augmentation added to it, the water cop-
tained before it can habituate it felf thereto, contijiuing in
tardity , (hall ftay behinde ? namely a ftern, where of coni^'
quence it (hall mount, and abate for the fame at the prow. Tb^^
effcft is undoubted and manifeft, and may hourly be experinie*^'
ted •, in which I defire that for the prefent three particulars m^.V
be noted. The flrft is, that to make the water to rile on on^
fide of the veifel, there is no need of new water, nor that it i'^^^
thither, forfaking the other fide. The iecond is, that the water
in th^ middle doth not rife or fall notably, unlelfe the courfe o
the Bark were not befor^^^ that very fwift, and the (hock or otUcr
arreft that held « exceeding firong andfudden, in which cafe it^
poffihle, that im>1; only ail the water might run forwards, buj
that the greater part thereof might iffue forth of the Bark : an<l
the fame alfo would enfue , whiift that being under fail in ^
fmooth courfe, a moft violent impetus (hould, upon an inftaii^)
overtake it : But when to its calme motion there ii» added a ino-
derate retardation or inciution, the middle parts (as I faid) uP-
obfeivedly rife and fall : and the other parts, according as they
a^-c necrer to the middle, rife the leffc , and the more r^i^iote,
more. . The third is, that whereas the parts about the fliidlt da
make little alterati^>n in riimgand falling, in refpe6: of ^^^^
ter^ of t^e fides , pn the contrary, they run forwards and back'
waixiLi very mud), incomparifori of th^ extream^; Now, i^/
Mailers, that which the Bark doth, in refpeft of the water by
cont:^ine4, ^hat which, the water contained doth? ?T
fpeft of theBarkiits container, is the fclf fame, to an hair,wi^
tha; which the Mediterranean VefTcl doth, in refpeft of the
^er^j^it contained, and that which the waters contained ^^^^
reig.e&oJE the Mediterranean /Veffel their container. It fpH^^*
cth apw that we demon ft I at€ how, andfinrwhatn^^nner it is
tha^tqthe M^ditf rrane, and all the other Straits j and in ^ ^^^jj
^lU^'parts of the Earth do all move, with a motion notal^ 7
unev^j thq^^gl^jio j^Q^ion that is not regular and miion'^'^^
jEhcrfby affigned to all the fai4 Globe tiakei^ polkaiveJy^-

Simp-

jDlALOGUEllI. ^

S I M p. This Propofition, at firft fight to me, that atn neither
Geometrician nor Aftronomer, hath the appearance of a very
gt'eat Paradox^ and if it fliould be true, that the motion of the
^'Wc 5 being regular, that of the parts, Which are all united to
their whole, may be irregular, the Paradox will overthrow the
Axiome that affirmeth, tandem ejfe ratiomm totins & far-

Salv. I will dcmonftrate my Paradox, and leave it to your
care, Simplictm, to defend the Axiome from it, or eUe to re-
concile them^ and my demonftration fhall be fliort and fa-
«^iliar, depending on the things largely handled in our prcce-
dent conferences, wichoiit introducing the leaft fyllable, in fa-
vour of the flux and reflux.

We have faid, ,that the motions affigned to the Terreftrial
Cllobc are two , the firft Annual, made by its centre about the
^circumference of the Grand Orb, under the Ecliptick, according
to the order of the Signes, that isj from Weft to Eaft \ the other
«^ade by the faid Globe revolving about its own cencrein twenty
four hours^ and this likewife from Weft to Eaft : though a-
bout an Axis fomcwhat inclined, and not equidiftant from chat
of the Annual converfion. From the mixture of thefe two mo-
tions, each of it felf uniform, I fay, that there doth refult an
Uneven and acformed motion in the parts of che Earth. Which,
that it may the more eafily be underftood, 1 will explain, by
drawing a Scheme thereof And ntft, about the centre A \jn
fig, I. of this Dialogue'] I willdefcribe the circumferetice of
Grand Orb B C , in which any poiiit being taken, as B,
about it as a centre we will defcribe this leffer circle D E F G,
reprefeniing the Terreftrial Globe ; the which we will fuppofe
to runthorow the whole circumference of the Grand Orb, with
its centreB, from the Weft towards the Eaft, that is from the
part B towards G^ and moreover we will iuppole the Terre-
ftrial Globe to turn about its own centre B likewile trom Weft
to Eaft 5 that is , according to the fucceflion of the points^
E> E F G , in the fpace of twenty four hours. Biit here
Ottght carefully to note, that a circle turning round upon its
own ceiure, each part of it inuft, at different times, ^™ with
<^ontraty motions: the which i. ttianifeft, confidcnng that whi ft
^l^e parts of the circumference, about the point D move to the
lefthand^^that is,toWardsE, the oppofite parts that are about
approach to the right hand, thit is, toW^^^^ G^ fo that wheri
parts D (hall be inF, their motion fltall^e tx>ntrary to what
it was before, when it was in D. Furthermdte , the lame time
that the parts E defcend, if I may fo f peak, towards F, thofe iri
G afcend towards D. U being therefore prefuppofed, that

there

385)

horo the pans of
th: terrefirialf
Ghhe accchrAti
and retard.

The parts cf 4
Circle reguUrly
moved, ahut its
o^n centre move
divers times with
contrary motions.

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

79 o

G A L I L ^ u s, hit Syflcme;

^^Th^ mixture of there are fuch contrarieties of motions in the parts of the Terre-
aJJa7\S7ilZ ^^'^1 Surface, whilft it turneth round upon its own centre, it is
w/, cAufeth the neccflary, that in con joy ning this Diurnal Motion, with the other

Zl^^VJ" Annual, there do refult an abfohite motion for the parts of the

monon oj tne parts . j n • 1 o r • i

of tht terrefirui ^aid Terreltriai Superhcies, one while very accelerate, and ano-
GUe, ther while as flow again. The which is manifcft , confidering

firft the parts about D, the abfolute motion of which fliiiH
cxtream fwifr^ as that which proceedeth from two motions made
both one way, namely , towards the left hand i the firft
which is part of the Annual Motion, common to all the parts of
the Globe, the other is that of the faid point D., carried likewil^
to the left, by the Diurnal Pvevolution j (o that, in this cafe, the
Diurnal mo.ioa increafeth and accelerateth the Annual. The
contrary to which happenethin the oppolite partf, which, whilft
it is by the common annual motion carried, together with the
whole Globe, towards the left, it happeneth to be carried by the
Diurnal converfion alfo towards the right : fo that the Diur-
nal motion by that means detrafteth from the Annual , where-
upon the abfolute motion, refulting from the compofition of^oth
the other, is much retarded. Again, about the points E
the abfolute motion becometh in a manner equal to the Innpl^
Annual one, in regard that little or nothing increafeth or dimi*
niflieth it, as not tending either to the left hand, or to the right?
but downwards and upwards. We will conclude therefore, that
like as it is true, that the naption of the whole Globe, and oi
each of its parts, would be equal and uniforme, in cafe they did
move with one fingle motion, whether it were the meer Annual,
or the fingle Diurnal Revolution, fo it is requifite, that mixing
thofe two motions together, there do refult thence for the p^rts
of the faid Globe irregular motions, one while accelerated, an^
another while retarded, by means of the additions or fubftrafti-
ons of the Diurnal converfion from the annual circulation. So
that, if it be true (and moft true it is, as experience proves^ that
the acceleration and retardation of the motion of the Vcf-
fel, makes water contained therein to run to and again the long
wayes of it, and to tile and fall in its extrcames, who will make
fcrupie of granting, that the faid efFefi may, nay ought to fuc-
ceed in the Sea-waters, contained within their Veffels, fubjefl:
fuch like alterations, and efpecially in thofe that diftend thcni'
felves long- wayes from Weft to Eaft, which is the courfe that
the motipn. of thofe lame Veffels fteercth ? Now this is
n^oft potent and primary caufe of the ebbing and flowing, vv^^^'
o^t the which no fucli effeft would enfue. But becaufe the p^r-

The moji potent
4ttdptimarj eatife
•f the ehktrtg aid

ticular accidents arc many and various, that in feveral places an*
times ^bfcrvcd, ;,v^^^ muft of neceffity have dependant

cc
on

4
i

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

Dialogue IV.

on other diftcrenc concomitant caufes, although they ought all
to have connexion with the primary ; therefare it is convenient
that we propound and examine the fcveral accidents that may
f>e tht caufes of fuch diftercnt cfFeSs.

The fiift of which is, that when ever the water, by means of a
notable retardation or acceleration of the motion of the Veflll,
its container, (hall have acquired a caufc of running towaids this
or that cxtrelm, and fliall be raifed in the one, and abated in the
other it fliall not neverthekffe continue, for any time in that
fiate,' when once the primary caufe is ceafed: but by vertue of
its own gravity and natural inclination to level and grow, even ic
fliall fpeedily return backwards of its own accord, and, as being
grave and fluid, fliall not only move towards Mqutltiyrmm but
being impelled by its own tmpetHS, fliall go beyond it, riling in
the part, where before it was loweft, nor fliall ic fiay here, but
returning backwards anew, with more reiterated reciprocations of
its undulations, it fliall give us to know, that it will not f,om a
velocity of motion, once conceived reduce it iclf, in an ir ftant,
to the privation thereof, and to the ftate of reft, but will luccef-
fiveiv bvdecreafing a little andahttle, reduce K felf unto the
fame iuft in the fame manner as we fee a weight hanging at a
cord ' after it hath been once removed from its ftate of reft, that
h from its perpendicularity, of its own accord, to return thither
and fettle it felf, but not till fuch time as it fliall have often
paft to one fide, and to the other ^ with its rqciprocall vi-
brations. ^ . . , i , r

The fecond accident to be obferved is, that the before-
<leclarcd reciprocations of motion come to be made and repeated
with greater or leflfer frequency, that is, under fliorter or longer
timesfaccordingto the different lengths of the Veffels contain-
ing the waters^ fo that in the fliorter fpaces the recp.ocati-
ons are more frequent, and in the longer more rare : ,uft as in
the Wr example of pendent bodies the vibrations of thofe
that are hanged to longer cords arefeen to be leffe frequent,
than thofe of them that hang at fliorter ftnngs .

Andhere,fora third obfervation, « J^^^f ""f,;.? ".E^
onelv theareateror leffer length of the Veff.l is a caule that

theXt Seth i- -ipr-tions -^-'S^^^^^

the greater or leffer profundity worketh the fame ettett. And

nha'pp: :th, thatof'waters contained in --P-f^jf

length but of unequal depth, that which fliall be the deepeit,

itrundulat'ons und'et fliorter times, and the reciprocati-

^f\f^T''TZTs^:^oIy^o^^ -otci, and di-
k l^onrthly, there are two enecib wv/ { , . , ^ . ,

\^m\y obferved, which the witet Wctkcth m thofe its v?bf*-

3<?i

Spf»drjf accidertJi
that happen in tht
ehbitt^s & flowtvjrs
The fi^^t dcci"
dert.

The Water rat'
fed iff o*it end of
the ye(fel retfru^
eth of its ff'f t»
i£quiUbriuni.

In the ptortfr
KflftheunduU-*
ttons ofivaters 4Te
mtrcfreqtteftt.

Tht greater
profditditf mal^th
the HndnUtions of
waters more fr^i
qttfnt.

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

5^ i G. G A L I L ^ u s, his Syflcme.

& tioHs J thc onc IS its r'lfing and falling alternately towards th^
^trlamflrn^Yth'e ^ind othet extremity ^ the other is its moving and running?
f^ejfei.Mnd runneth fo Ipcak, Horizontally torwards and backwards. Which two dit-
lidB. iQVQnt motions differently refide in divers parts of thc Water :

for its extream parts arc thole which moft eminently rile and fall?
thofe in thc middle never abfolutely moving upwards and down-
ward& ^ of the reft fucceffively thole that are neereft to the ex-
treams rife and fall proportionally more than the reiiiotc : but on
the contrary, touching thc other progreffive motion forwards
and backwards, the middle parts move notably, going and r^'
turning, and the waters that are in the extream parts gain
ground at all j lave onely in cafe that in their rifing they ovef
flow their banks, and break forth of their firft channel and re-
ceptacle but where there is the obftacle of banks to keep them
in, they onely riCc and fall j which »yet hinderetli not the waters
rn the middle from fluduating to and again which likewifc
the other parts do in proportion , undulating more or leffe,
according as they are neerer or more remote from the middle-
yin Mccidcnt of The fifth particular accident ought thc more attentively
ff>f Earths motioMs confidcrcd, in that it is impoflible to reprelent the effcfl: th^*'^'
TJced t»^lraa$ce an experiment or example , and the accident is thi5>-

h ^rt. the veffels by us framed with art, and moved, as the above-

named Bark, one while more, and another while leffe fwiftly>
thc acceleration and retardation is imparted in the fame manner
to all the vcflel, and to every part of it j fo that whilft ^. g, the
Bark forbeareth to move, the parts precedent retard no more
than the fubfequent, but all equally partake of the fame re-
tardment 5 and . the felf-fame holds true of the acceleration)
namely , that conferring on the Bark a new caule of ff^^'
tcr velocity , the Prow and Poop both accelerate in one and
the fame manner. But in huge great vcfTels, fuch as are the very
long bottdmes of Seas, albeit they alfo are no other than cer-
tain cavities made in the folidity of the Terreftrial Globe,
it alwayes admirably happcneth , that their extreams do not
unitedly equall , and at the fame moments of time increafe
arKf diminifti their motion, but it happcneth that when one of its
extreames hath, by vertue of the commixtion of the tv^^
Motions, Diurnal, and Annual, greatly retarded its velocity^
thc other extream is animated with an extream fwift moti^^*
Which for the better underftanding of it we will explain ?
fuming a Scheme like to the former ^ in which if we do but i^?'
pofe a traft of Sea to be long , 'Z'. ^. a fourth part , as is the
B C [i;, pjg ^ -j becaufe tte parts B are , as hath bee;n already
declared, very fwift in motion, by reafon of the union of the
two motions aititti^d and annual, towards one and the fame ^ff^

but

I ALO«UK.

IV.

tut the part C at the fame time is retarded in its motion , as be
it^g deprived of the progreffion dependant on the diurnal motion:

we fuppofe, I fay, a traft of Sea as long as the arch B C , we
have already feen, that its extreams fliall move in the fame time
with great inequality. And extrearaly different would ihevelo*
cities of a traft of Sea be that is in length a femicircle 5 and pla-
^d in the pofition BCD, in regard that the extream B would

in a moft accelerate motion , and the other in a moft flow
^ and the intermediate parts towards C , woirld be in a
"Moderate motion. And according a^ the faid trafis of Sea fliall

fliorter , they fliall leffe participate of this extravagant acci-
*^ent , of being in fome hours of the day with their parts diverfly
^ffefted by velocity and tardity of motion. So that, if,as in the firft
cafe, we fee by experience that the acceleration and retardation ^
though equally imparted to all the parts of the conteining Vcffei,

thecauie that the water colitained,fluSuates too and again^what
may we think would happen in a Veffel fo admirably difpofed,
that retardation and acceleration of motion is very unequally
contributed to its parts ? Certainly we muft needs grant that
S^^eater and moi^ wonderful caufes of the commotions in the
Water ought to be looked for. And though it may feem im-
poffible to fome, that in artificial Machines and Veffels we fliould
he able to experiment the cffeas of fuch an accident*, yctne-
^erthelefle it is not abfolutely impoflible to be done j and I have

me the model of an Engine, in which the effeft of thefe admi-
table commixtions of motions may be particularly obfcrvcd. But
*s to what concerns our prefent pirpofe , that which you may
^^^e hitherto comprehended with your imagination may fuf-
fice.

S A G R, 1 for my own particular very well conceive that this
^mirable accident ought neceffarily to evene in the Straights of
and efpecially in thofe chat diftend therafelves for a great
*^«gth from Weft to Eaft ; namely according to the courfexrf
motions of the Terreftrial Globes and a^ it is in a certain
'^^nner unthought of , and without a prefident among the moti-
ons pofliblc to be made by us , fo is not hard for me to believe,
^bat efFefts may be derived from the fame, which are not to be i-
^itatedby our artificial experiments. .

Salv. Thefe things being deqUred , It is time that we pro-
to examine the particular accidents , which, together with
<heir diverfities , are obferved by experience in the ebbii^ and
"^^ing of the waters. And firft we need not think it hard to
?^^ffe whence it happeneth, that in Lakes, Pooles,anci alto in the edsf thepMrncn^
^ff^^ Seas there is no notable flux and reflux^ the which harfi ^;;^;;t'2t
the one is, that by reafonof the ftort- ^in^sandJUwinis.

I — ^as

^Wo very folidreafons.

Ddd

jnefle

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

594 G, Gal I LIE ns y his Syjleme.

Second c4u(is neflc of the Vt flel , in its accjuiiirg in liveral hours of tlie^lay
^■hjm [mall Seas fevcraL dcffFccs of velocitv , they arc with very little difference

4nU iM LmK^s there , , . ^ i, • r n i J *1 ^ CtiUiC'

4renoehbif>gs dnd acqiured by all its parts j tor as well the precedent as tlieiuuic
jlovfiftgs, quent , that is to fay, both the Eaftern and VVeftern paits , tlo

accelerate and retard alnioft in the fame manner ^ and Witn^
making that alteration by little and little , and not by giving the
motion of the conteining Veffel a fuddcn check, and retard-
ment, or a fiidden and great impulfe or acceleration j both »^
and all its parts, come to be gently and equally impreifcd witn
the fame degrees of velocity , from which uniformity ic foUoW-
cth, that alio the conteined water- with but fmall refiftancc airiu
oppofition, rcceiveth the fame imprefllons , and by confequencc
doth give but very obfcure figncs of its rifing or falling , or of it*
running towards one part or another. The which effeft is likewii^
manifeftly to be feen in the little artificial Vcifels , wherein th^
contained water doth receive tlie felf fame impreffions of veloci'
ty h when ever the acceleration and retardation is made by gentl<^
and uniform proportion. But in the Straights and Bays that for ^
great length diftend themfclves from Eaft to Weft , the accele-
ration and retardation is more notable and more imeven , ^
that one of its extrcams (hall be much retarded in motion ,
the other (hall at the fame time move very fwiftly : Thefc^^^
procal libration or levelling of the water proceeding from the if^f'
fetrn thu it had conceived from the motion of its contained'
The which libration, as hath been noted , hath its undulation^
very frequent in Cmall Vcffels j from whence eniues , that thoUg^^
there do re fide in the Terreftrial motions the caufeof confr^'
ring pn the waters a motion bnely from twelve hours to twel^^
hours, for that the motion of the conteining Velfcls do^^'
treamJy accelerate and extreamly retard but once every ^^Y'
and no more , yet neverthelelfe this fame fecond caufe^epen -
ing on the gravity of the water which ftriveth to reduce it lel
equilibration V and that according to the (hortneffe of the Ve
fel hath its reciprocations of one, two, three, or more hours ,
intermixing with the firft, which alfo it felf in fmall VcS^^^ ^
very little ) it becommeth upon the whole altogether infcnlAbi '
For the.primary caufe , which hath the periods of twelve hou^^f*
having not made an end of imprinting the precedent comn^^"^
on , it is overtaken and oppofed by the other fecond 5 d^P^/\
dant on the waters own weight , which according to the hrev
and profundity of the Vclfci , hath the time of itsundulatioi^^. ^
one, two, tkee, four , or more hours ^ and this cont^^
with?the other former one, difturbeth and removcth it ?
ii™itting, itto conae to the height , no nor to the half of its tno ^
on 5 ^Rd by ;this conteftation the evidence of the ^^^^^^^^l^r.

Dialogue.

iv.

355

flowing is wholly annihilated, or at leaft very imich obfcured.
Ipaffe bv the continual alteration of the air , which d.fqu.etnig
the water; permits us not to come to a certainty whether any ,
ihouph burimall , encreafe or abatement of half an inch, or
Icffe ; do rcfide in the Straights , or receptacles of water not a-
bove a degree or two in length.

I come in the fccond place to refolve the queftion , why, there
not refiding any vertue in the primary principle of coinmovmg
the waters f fave onely every twelve hours that ,s to fay once
by the greateft velocity, and once by ^ the greateft tarduy of
motion ? the cbbings and flowings (hould yet ncvertheleffe ap-
pear to be every fix hours. To which is aniwered, that this de-
termination camiot any wayes be taken from the primary caule
onely ; but there is a neceOky of introducing the fecondary cau-
ses , as namely the greater or leffe length of the Veffels , and
'he greater or kffe depth of the waters in tbem contemcd.
Which caufcs although they have not any operation in the moti-
ons of the waters , tho(e operations belonging to the fole prima^
ry caufe without which no ebbing or flowing would happen,
yetnevertheleffe they have a principallhare in determ.mng the
rimerorriods of ?he reciprocations, and herein tjeir mflu,
ence irro^pcwcrful , that the primary caufc muft of force give
way unrothem. The period of fix hours therefore is no more
proper or natural than thofe of other intervals of tiines though
indeed its the moft obfcrved , a. agreeing with our Mediterratie,
which was the onely Sea that for many Ages was navigated :
though neither is -that period obfcrved in all its parts i or
that in feme more anguft places , fuch as are the "^Uc
fpont , and the JEgean Sea , the periods are much ftorter ,
and a fo very divers. an-.ongft themfelves , for ff ^^^'
fitics ard their caufes incomprehenfible to Ar,Jiotle , fome
fay \ha after he had a long time obferved it upon fome
cUff' Tlr Lnt beine brought to defperation , he threw
^^UoS^-'P- ' and voluntarily drowned

'"She third place we havethe r^^^^fy^:^trt^
itcommcthtopaffe,-thatlome Seks, ^'^'^'^^f J'^^^^^^^
theKedSea, are aliiK.ft altogether exem^^^^^^^^^^^ 1^ kaft t
happencth becaufe their length ex^^n^et^^^^^^^
Weft, but rather tranfver y from ^^^^^^^^^

weft, but the motions of J^^J^^^^^ g

he impulfes of the water by ^J^^^^^f Mallei to parallel ;

;vthe Meridians, and do "Ot rnovej p^^^^^^ ^^^^^^^
ii^iornuch that in the Seas that cxtcu , .

wardst Poles , aU that che contrary way are narrow , the.. «

The

. . eafoH gi-
ven^ t»hj the eB^
htngs andpwiniis^
for the moft farh
are every fx
hoHrs>

The cdup vfhf
fome Seat, thou£h
very long , fuftr, .
no ehhng AfiA
flovfiftg^

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

3p5 G. Galu^us, his Syjleme.

no caufe of ebbing and flowing , favc onely by the participation
of anorher Sea , wherewith it hath communication , that is fu^-
jeft to great commotions.
Ebhings and Iti the foutth place we (hall very cafily find out the reafon
fiomngswhy^rea- why the fluxcs and refluxes are greateft, as to the waters riling
mittej of gu/phs, and talhng in the utmoft extremities of Gulphs , and Icaft m tde
mfdJlT^aris intermediate parts \ as daily experience flieweth here in Venice^
c farts. \fmg in the farther end of the Adriatick^ Sea , where that diffe-
rence commonly amounts to five or fix feet ^ but in the places
of theMediterrane , far diftmt from the extreams , that mutati-
on is very fmali , as in the Ifles of Corfica and Sardinnia ,

and

in the Strands of Kome and Ligorne , where it exceeds not halfa
foot ; We fliall Uiiderftand alfo, why on the contrary 5 whcf^
the rifings and failings arc fmall , the courfes and recouricsarc
great : 1 fay it is an eafie thing to underftand the caufes of theft
accidents 5 feeing that we meet with many ma nifcft occurrences
of the fame nature in every kind of Velfel by us artificially coin-
pofed , in which the fame eflfefts are obferved naturally to fol-
low upon our moving it unevenly, that is, one while fafter , an^^
another while flower-
9vhj in Harrow Morcovcr , confidcring in the fifth place , that the fanic
If" he tlr^r^t "l^^^^^^X ^^^^^ being moved, though but gently, in a fpatious
more fwift than in Channel , comming aftcrwards to go through a narrow paflage,
larger, ^ill of necefl[ity run, with great violence, we fliall not finde it har^I

to comprehend the caufe of the great Currents that are made
in the narrow Channel that fcparateth Calabria from SicilU-
for that all the Water that, by the fpacioufncffe of the ifc
•and by the lonich^ Gulph, happens to be pent in the Eaftertt
-part of the Sea, though it do in that, by reafon of its largeneft,
gently defcend towards the Weft, yet neverthelcfle, in that it
IS pent up in the Bofphorm^ it floweth with great violence be-
tween^SpUa ztid Catibdk^ and make th a great agitation. Lik^^^
which, ind much greater, isfaid to be betwixt Africa and the
gredt tfle of St. Ldren%Oy where the Waters of the two vaft
Seas, Indian and Ethtopick,^ that lie round it muft needs be
ftraightned into a lefle Channel between thefaid Ifle and the
Ethiopian GoaiCi. And the Currents muft needs be very gre^^
'ifi the Straights io£ , Magellams ^ which joyne together tbf
• vaft Oceans of Ethiopia^ and Del Zitr^ called alfo the Facff^

A dtfcufion of ft *{!>Hbws now,: in the fixth place, that to render a reafon of
{:S7i^^^^^^^^ more abftrufe and incredible accidents, which are obfef-
inthe ebhing and ved ftfppn this occafion, We make a coufidcrable reflection npo^^
fin^i^'i' ^**« tW principal caufes of ebbings and flowings, afterwarJ^

^^"^^^^iiig atid mixing them together. The firft and ifiiPp^

DiALOGU E I V.

of which is (as hath often been faid) the determinate accelera*
tion and retardation of the parts of the Earth, from whence
"Ae Waters have a determinate period put to their decurfions
towards the Eaft, and return towards the Weft, in the time of
twenty four hours. The other is that which dcpendeth on the pro-
per gravity of the Water, which being once commoved by the
primary caufe, feeketh, in the next place, to reduce it felf to
H.^ilihriMm-i with iterated reciprocations , which are not deter-
'^ined by one fole and prefixed time , but have as maity varie*
^ies of times as are the different lengths and profundities of the
receptacles, and Straights of Seas ^ and by what dependcth on
thisiecond principle, they would ebbe and flow, fome in one
f^our, others in two, in four, in fix, in eight> in ten, Sec. Now if
^e begin to put together the firft caufe, which hath its fet Period
from twelve hours to twelve hours, with fome one of the fecon-
^^^'^y, that hath its Period 'utrb, grat, from five hours to five
'^^urs, it would come to pafTe, that at fometimes the primary
caufe and Secondary would accord to make impulfes both one
s^nd the lame way j and in this concurrency , and (as one may call
i^) unanimous confpiration the flowings {hail be great. At other
times it happening that the primary impulfe doth, in a certain
manner, oppofe that which the fecondary Period would make^
and inthisconteftone of the Principles being taken away, that
which the other would give, will weaken the commotion of the
Waters, and the Sea will return to a very tranquil State, and
almoft immoveable. And at other times, according as the two
rforelald Principles (hall neither altogether con teft, nor altoge-
*^ concur, there (hall be other kinds ^f alterations made in
the increafe and diminution of the ebbing and flowing. It may
fikewife fall out that two vSeas , confiderably great and which
^muhicate by fome narrow Channel, may chance to li^tve^by
Won of the mixtion of the- two Principles of motion , one
^aufe to flow at the time that the other hath caufe to oiove *
^trary wy s in which cafe in the Channel, whereby they dil.
feibbguc themfelves into each oflier , there do extraordinary
-onturbations infoe, ;with oppofite and vorndcj^^^^

5S7

^^iuuroations mmc, witit v^j^j^v^nt^ — — - - .

*oft dangerous beltings and-breikings , as frequent rekaons
■H^Periences do aflbre us. From fuch like difcordant mott-
S ^^naent not onely on the <^^^^?o^^ ^

uependent not onciy wi «rc umn-." r— - , - v
but very much alfoupoii thedlfFerent t"of"n<^'"« f ^^i^
^«,whKh have the faid intercourfe there do happen at fome-
>es different commotions ill ithc Waters, -irrtgular, and that
be reduced to no rules of t,bfervation the reafons ot which
■*>ave much troubled, andalwayes db trouble ManncFSy 4or that
tfiey meet with them without feeing either iimpulfe of winds, etc

other

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8 G. G A L I L /B u s, Ms Syjlcme.

tJther eminent acreal alteration that might occafionthe faitifc 7
which difturbance of the Air we ought to make great account
in other accidents, and to take it for a third and accidental
caufe, able to alter very much the obfcrvation of the effects de-
pending on thefecondary and more eflential caufes. And it is
not to be doubted, but that impetuous wiudes, continuing to
blow, for example, from the Eaft, ihey fhall retein the Waters
and prohibit the reflux or ebbing whereupon the fccond ana
third reply of the flux or tide overtaking the former, at the
hours prefixed, they will fwell very high j and being thui> born
up for foinc dayes, by the ftrength of the Winds, they ftiall i'^^
inore than ufual, making extraordinary inundations.

We ought alfo, (and this fliall ferve for a feventh Probleme)
to take notice of another caufe of motion dependant on the
great abundance of the Waters of great Rivers that difchaige
th ekttfe vhf, themfelves into Seas of no great capacity, whereupon in the
in feme ndrro^ Straics or ^t/fWi that communicatc with thofc Scas, the Watcf^
Channels, we fee ^^^^ j.^ ^.^^ alwavs oue wav : 38 it happeueth in the Jhracr

the SeA'W4ters TKH ^ , i i ^ /r ■ t i i i .^veS

4lwdjesonew^, m BofprJortis below CottjiantiHople , where the water always'
runneth from the Blach^Sea^ towards the Tropontk : For in the
faid Black: Sea by reafon of its fliortneffc , the principal cauies
of ebbing and flowing are but of fmall force. But, on the con-
trary 5 very great Rivers falling into the fame , thofe huge oe-
fluxions of water being to pafle and difgorge themfelves by tn^
•Orcurrem. the Straight , the ^courfe is there very notable and alwaycs to-
wards the South. Where moreover we ought to take notice^ that
the faid Straight or Channel , albeit very narrow , is not fubjefl
to perturbations , as the Straight of 5^///^ and Qrj'W^ i for th*^
thathaththeJB/^t/^-5c^ above towards the North > and the P']^'
pontis^thc JEgearj ^ and the Mediterranean Seas joyned untoit>
though by a long trafi towards the South j but now, as we have
obferved j the Seas, though of never fo great length , lyii^§ v<oti
and South, are not much fubjeSto ebbingsaad flowing^ ? J^JJ
becaufethc *Si^i/i>« Straight fituate between the parts ot tne
Mediterrane diftended for a long trail or difl:ance from Weft
Eaft , that is, according to the courfe of the fluxes and refluxes?
therefore in this the ^agitations are very great , and would
much nrOre violent between Hercules Fillars ^ in c^^^
Straight of Gibraltar did open lelfe j and thofe of the Straight ^
Magellancf are reported to be extraordinary violent.

This is whatj for. the prefent, cometh into my mind to fay ^^^j
you about the cai^fes of this firft period diurnal of the Ti^^^; ^^^^
^ts various accidents , touching which, if you have any th'^8
^^^r , you may let us hear it , that fo we may afterwat^i^ pt^
ceedtothe othet twoperiods, monethly and annual.

Dialogue

IV.

3P9

Simp. In my opinion, it cannot be denied, bat that ymt dii^
courle cariieth with it much of probability, arguing, as we fay,
fx fuppofitioae , namely, granting that the Earth moveth with
the two motions afligne'd it by CopernicM : but if that motion Thtff;pv,htfis
te difproved, all that you have faid is vain, and inf.gnificant : '[jj;;^'^;^
and for the difprcval of that Hypotheftf , it is very maniteltJy ^/^^
hinted by your Dilcourfe it felf. You, with the fuppofition of cf^ofid.
thetwo Terreftrial motions, give a reafon of the ebbing and
flowing i and then again, arguing circularly, from the ebbing
and flowing draw the reafon and confirmation ot thofc very
motions i aud fo proceeding to a more fpccious Ditcouife, you
% that the Water, as being a fluid body, and not tenaciouflj
annexed to the Earth, is not coiiftraincd pnnaually to obey eve-
ry of its motions, from which you afterwards infer its ebbing
and flowing, Now I, according to your own method, argue
the quite contrary, and fay ; tlie Air is much more tenuous, and
fltJid than the Water, and leffe annexed to the Earths fupcrfici-
to which the Water, if it be foe nothing elfe, yet by reafon
of its gravity that prctTeth down upon the lame more than the
%ht Air adhereth i therefore the Air is much obhged to fol-
low the motions of the Earth : and therefore were it lo, that the
Earthdid move in that manner, we the inhabitants ot it, and
carried, round with like velocity by it, ought perpetually to feel
•a Winde from the Eaft that beateth upon us with intolerable
fercc. And that fo it ought to fall out, quotidian experience af-
;fnreth us ; for if with onely riding poft, at the fpced of eight ot
'•feiimiles an hour in the tranquil Air, thcincountering of it with
^r faee feemeth to us a Winde that doth not lightly blow upon
=^tis,what fliould we expeft from our rapid courie of 800. or a
'thoufand miles an hour, aga'nft the Air, that is, free from that
motion > And yet 4 notwithfianding. wc: cannot pecce.ve any

'^'s:fv'''¥X^)caion thathathmuchof likelihood in it, 1 j,.
'eply, that its true, the Air is of greater tenuity =»f '^^"J ^^^.7? n.ade .««/f ,h,
W reafon of its levity, leffe adherent to the Earth than Water lo T^-
much more grave and 'bulky, but yet the confequence is falfe -A''' ^';*'- . ^
"<.umorLgravt «i ; ; „,,v,pI« that upOn account +Cotouicn<».

tW vou infer from thete quaUt.es; namely, that up ^

of that its levity, tennity, and leffe adherence to the Earth „
fliouW be more exempt than, the Water J';"^^"^;^;.
Terreftrial Moti..,loastha.-to^^

•^aufeof th^ebbing and flowing ot the Water affigned by us,
conGfteth in the Waters not following the unevenneffe of the
motieiiof its Vcffcl but retainingthe m]^tm conceived before,
' vvithouC

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2°K.B. 9,163

400

The JVater more
Mpt t9 conferve an
impetus coxcfivedy
then the Air*

L*^ht btdteseAfitr
to ke moved than
beavjy hnt lefs a^t
to conferve the mo"
tion^

Its more rMtonul
that the Air be
tommoved by the
merged fifrface of
the Fanh, than
bf the Celifiul
nation*

The rf^oUttiott of
the Earth cj»'
JSmid bj M neif
argument
from the ^/i^r.

G. G A n L /E u his Syfleme.

without dimiiiifliing or increafiiig it according to the precife rate
of its diminifliing or increafing in its Veffel. Becaufc therefore
that in the confervation and retention of the intfetus before con-
ceived, the dii'obedience to a new augmentation or diminution of
motion confiftech, that moveable that fliall be moft apt for fuch
a retention, fliall be alfo moft commodious to demonftrate the
elFcft that foUowerh in confequence of that retention. Now hoW
much the Water is difpofed to maintain fuch a conceived agita-
tion 5 though the caufes ceafe that imprefs the fame , the experi-
ence of the Seas cxtreamly difturbed by impetuous Winds flie^'
eth us i tl>e Billows of which, though the Air be grown calm, and
the Wind laid, for a long time after continue in motion ; As the
Sacred Poet pleafantly fings,

Qjial Valto Egeoy &c.'

And that long continuing rough afcer a ftorm , dependeth on
the gravity of the water ; For, as I have eUewhere faid, light bo-
dies are much cafier to be moved than the more grave, but
are fo much the lefs apt to conferve the motion imparted, when
once the moving caufe ceafeth. Whence it comes that the Airc>
as being of it felf very light and thin, is eafily mov'd by any v^^Y
fmall force, yet it is withall very unable to hold on its motion^
the Mover once ceafing. Therefore, as to the Aire which envi-
rons the Terreftrial Globe, I would fay, that by reafon of its
adhcrencc^it is no leiTe carried abbut therewith then the Water j
and efpecially that part which is contained in its veflel^j which
vefTels arc the valleys cnclofed with Mountains. And we may
with much more reafon affirm that this fame part of the Air is
carried round, and born forwards by the. rugged parts of the
Earth, rhan that the higher is whirl'd about by the motion of the
Heavens, as ye Peripatetickj maintain.

What hath been hitherto fpoken, feems to me a fuffici^l^^
£wcr to the allegacion of SimplrtiHs j yet neverthelefs witha neW
inftance And folutioti, founded upon an admirable experiment,!
will fijperabundancly fatisfie him , and confirm to Sagredns the
mobility of the Earth. I have told you that the Air, and in paf'
ticular that part of it which afcendeth not above the tops

of the

higheft Mdumains, is carried round by the uneven parts of ^

Earths furface .• fronh whence it fliould feem, that it muft of ^^"^

fequence come tdpafle, that in cafe the fuperficics of the Earth

Were nbt uneven , but fmooth and plain, no caufe would rcnjatfl

f^r drawing the Air alOng with ir, tir at Icaft for revolving i^ -

muchiiniformity. : Now the furface of thifs our Globe ^

all craggy ^nd Jugged, but there aire exceeding great cra&s

cvenj

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Dialogue. iV. , 4ci

'^ven, to wits the furfaces of very vaft Seas, which being alfo tac
remote from the continuate ledges of Mountains which environ

icem to have no faculty of carrying the fuper-ambient Ait
*long therewith : and not carrying it about, we may perceive what
Will of confequence enfwe in thofe places,
t'- S ! M ^. I was about to propofc the very fame difficulty ,which
I tiittvk is of great validity.

S A L V. You fay very well StntpliciHsSox from the not finding
'Hthe Air that which of confequence would tollow , did this our
Globe move round ^ you argue its immovcablenefTe. But in cafe
^hat this which you think ought of ncceffary confequence to b«
f<*und, be indeed by experience proved '.o be io i will you accept

for a futficient teftimony and an argument for the mobility of
*<jfaid Globed

Si Inthiscafe itisnotrequifite to argue with me alone,
fliould fo fall out, and that 1 could not comprehend the
tWeof, yet haply it might be known by others.
8 A L V. So that by playing with you.a man (hall never get,but
alwayeson the lofinghand , and therefore it would be better
t<» give over : Ncverthelefs, that we may not cheat our third mati
We will play on. We faid even now, and with fome addition we
feitterate it, that the Ayr as if it were a thin and fluid body, and
notfohdly conjoyned with the Earth, feem'dnot to be neccfli-
Uted to obey its motion i unlcffe fo far as the cragginefs of the
terreftrial luperficies, titaniports and carries with it a part thcrc-
comigious thereunto ■■, which doth not by any great fpace cx-
**«d the greateft altitude of Mountains : the which portion of Air
ought to be fo much lets repugnant to the terrcftrial converfion,
^y how much it is repleat with vapours, fumes, and exhalations, the vg^o**^^
**tters all participating of terroie qualities, and confequcotly ^^Zl'-^/^J/^
>T»t of their own nature to the fame motions. But where there are ,«„.
wanting the caufes of motion, that is, where the furface of the
"Globehath great levels, and where there is lefs mixture of the
"^fene vapours, there the caufewht reby the ajhbient Air is con-
■ft*Mned to cive entire obedience to the terreftrial converfion will
in parr , fo that in fuch places, whilft the Earth nevolveth to-
^«4theEaft, there will be continually a wind perceived which
beat upon us, blowing from the Eaft towards the Weft:
*>d fuch eales will be the more fenfible, where the revoiUtion of
^^^\obl U moft fwifci which will be in places more remote from
^''e Poles, and approaching to the greateft Circle of the diurnal
??nverfion. But no« de fa&io experience much confi.meth this
%»«fophical argumemation ; for in the fpatious Seas,and m the.r
'^Wts ftvoft remote from band,and fitoate under thc Torrid Zone,
'*«tisboandedby the fropicks, where there arc noncof t^e,

Eee

jp:^ C. G A L I L /E u s, his Syjlemc:

Conflani' gales fartic terfcftrial evaporations > we finde a perpetual gale move
t^iltt.r^s the Eaft with fo conftant a blaft, that ftilps by favour there-
thtvrtfi. of fail profperoufly to the We^-indias. And from the fame

coafting along the Mexican iDhore, they with the fame felicity pals
the FaeifickjOc^din towards the India s\ which to us are Eaft? but
Tht eouffe to the to thcm ate Weft. Whereas on the contrary the Courfe ft^^"
thence towards the Eaft is difficult and uncertain, and not to be

jie^tKe rePMrn atj- ' t A tCi

ficnit, made by the fame Rhumb, but muft vere more to Land-ward,

recover other Winds,which we may call accidentary and tumul-
tuary, produced from other Principles, as thofe that inhabit ^he
continent find by experience. Of which produfiions ©f Winds?
the Caufes are many and diflFerent, which fliall not at this time be
mnh from L^d mentioned. And thefe accidentary Winds are thofe which bloW
Si^' ''^^^ indifferently from all parts of the Eatth, and make rough the Se^s
remote from the Equinoftial, and environed by the rugged Sur-
face of the Earth j which is as much as to fay environed witf*
thofe perturbations of Air, that confound that primary Gale-
The which, in cafe thefe accidental impediments were removed,
would be continually felt, and cfpccially upon the Sea. NoW
fee how the efFeft of the Water and Air feem wonderfully
cord with the Celeftial obfervations, to confirm the mobility o
our Tcrreftrial Globe;
Amother ohferva- S A G R. I alfo for a final clofc will relate to you one particular?
^AiriToIZZl^' ^^i^** as I believe is unknown unto you , and which likcwife itiay
9i!lfth7moZTof fcrve to confirm the fame conclufion : You Sal<z;iatHS alledge^*^
tbeEsrth. That Accidcnt which Sailers meet with between the Tropicks '

I mean that perpetual Gale of Winde that beats upon thcmftoi^
the Eaftj of which I have an account from thofe that have maJ^Jf
times made the Voyage : And moreover (which is veryobfer*
vable) I underftand that the Mariners do not call it a fVi^^ ? but
* Which Wind by another ^ name, which I do not now remember , taken hapiy
uLZ if S from its fo fixed and conftant Tenor which when they have met
the Tradt-roind* With , they tie Up their flirouds and other cordage belonging ^
the Sails, and without any more need of touching them , thoug
they be in a fleep,they can continue their courfe. Now this conftajj^
Trade-wind was known to be fuch by its continual blowing ^^^^
out intenuptiont j for ifit were interrupted by other Windes,.i
would not have been acknowledged for a Angular Effeft ,
different from the reft : from which I will infer, That it maj
that alfo our Mediterranean Sea doth partake of the like accide^^^^
butit is not obferved,as being frequently altered by the con
ence of other windes. And this I fay, not without good groun ?
yea upon very probable conjefturcs whch came unto my knoV^^
ledge,froin that which tcndred it felf to my notice on pccafion^
the voyage that 1 made into S^ri^, going Conful for this Nation

I AlogUE

IV.

"^0 Aleppo-^ and this it is: That keeping a particular account an<l
^emoiial of the daycs of the departure and arrival of the Ships in
^hQ\^ott$o{ AUxandriajO(AlexaJ7dretta^^ndi\{\s of Venice in
Comparing fundry of thcin, which I did for my curiofity , I found
Aat in exaftnefs of account the returns hither, that is the voiages
from Eaft to Weft along the Mediterrane, arc made in lefs time
then the contrary courfes by 25. in the Hundred ; So that We itt
that one with another, the Eaftern windcs arc ftronger then the
Weftcrn.

S A L V. I am very glad I knOw this particuiar, which dbth not
a little make for the confirmation of the Earths mobility. And
although it may be alledged, That all the Water of the Mediter-
rane runs perpetually towards the Straits-mouth , as being t6
difimbogue into the Ocean, the waters of as many Rivers, as do
difcharge themfelves into the fame ^ I do not think that that cur-
rent can be fo great, as to be able of it felf alone to make fo no^
table a difference : which is alfo manifcft by obferving that the
water in the Fbaro of Sicily runneth back again no lefs towards
the Eaft than it runneth forwards towards the Weft.

Sagr. I thathavenota8»S'i;«/?//t/«J', an inclination to fatif-
fie any one befidcs my fcif, am fatisfied with what hath been faid
as to thisfirft particular : Therefore S^/'Z'/^^«x> when you think
it fit to proceed forward, I am prepared to hear you. '

S A L V. 1 (hall do as you command me, but. yet I would fain
hear the opinion alfo of Simpliciny^ from whofe judgement I can
argue how much I may promife to my felf touching thefe dif-
courfes from tlK Fer//?^i^e^/Vi^ Schools, if ever they fliould come
to their ears.

Simp. I defire not that ihy opinion Ihould fervc or ftand fot
^nicafure, whereby yoadiould judge of others thoughts s for

I have often faid, I am inconfiderable in theTc kinde of ftudiey,
and fuch things may come into the mindes of thofe that arc enter-

into the deepeft paffages of Philofophy, as 1 ^ojild never think
of ^ as having (according to the Proverb) fcarce kift hef Maid ;
y^tneverthelefs, to give you my fudden thoughts, I fliall tell
you, That of thofe effeds by you recounted,and particularly the
laft, there may in my judgement very ^^^^^^'^^^^^^^
without the Earths rnobility, by the n^obihty of the to^^
ly^iever introducing any novelty more, than the mverfion of
that which you your felf propofe unto us. It hath been received
^y the FerLteLk Schools, that the Element of Fire and alfo a
g^eatpartofthcAireiscarried about according to the Diurnal
^onverfion from Eaft to Weft, by the contaft of the Concave of
the Lunar Orb, as by the Veffel their contamer. Now without
going out of your track, I will that we determine the Qsantity ff
■ ^ Eeea Oit

'403

The voiages intbt
Mediterrdne from
Esfi to Weft arc
made jhorter
times than frm
fVefi to £afi.

Ititdemonfir/l^
ted inverting the
argnment -> thdc
the perpetual mo»
tien of the %Air
from Ea^ to Weft
cometh from the
mtitn of Heaven^

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;^o4 G. G A L I L ^ u s ^ Syflme.

jtis demonjlrAted thc Aire which pirtakcth of tlut inotioii to diflend fo low as to
tm;tni>,g the ar- tiic Tops of the hi^lieft Hills, and that likewile they would reach

ffuwem ^ that the r r P r • i- i • i t U'nh

p*rpr/»j/»wf/o«€/ to the Earth, ii thole Moun tarns did not nnpcde them , wnicii
l^rrS"'** h ^Sf^^^^ ^^^'^ v^\\2it you fay : For as you afFirni, the Air, which ts
%m tlet^TJof '^^^^"^^^^^ by ledges of Mountains, to be carried about by the
Heaven. afpetity of the moveable Earth j wc On the contrary lay, That

the whole Element of Air is carried about by the motion of
Heaven) that part only excepted which lyeth below thofe bodies,
which is hir.dred by the afperiiy of the immoveable Earth. And
whereas you laid, That in cafe that afperity (hould be removed,
the Air would alfo ceafe to be. whirld about j we may fay>
That the faid afperity being removed, the whole Aire would con-
tinue its motion. \V hereupon, becaufe the furfaces of fpacioUS
Seas are fmooth, and even ^ the Aifs motion fliall continue upon
thofe, alwaies blowing from the Eaft : And this is more fenfibly
perceived in Climates lying under the Line, and within the Tro-
pickS) where the motion of Heaven is fwiftcr j and like as tHasX
Celeftial motion is able to bear before it all the Air that is at
liberty, fo we may very rationally affirm that it contributeth the
fame motion to the Water moveable, as being fluid and not con-^
Themciioncf the neded to the immobility of the Earth ; And with fo much the
prater dependeth ^Qrc confidcncc may we affirm the fame, in that by your con-
HeMvdi!^^" feflion,that motion ought to be very fmall in refcfl: of the 'efficient
Caufe i which begirting in a natural day the whole Terreftri^'
Globe, paffeth many hundreds of miles an hour, and efpecially
towards the Equino&ial i whereas in the currents of the open Sea?
it movcth but very few miles an hour. And thus the voiages to-
wards the Weftfliall come to be commodious and expeditious,
not onely by reafonofthe perpetual Eaftern Gale , but of the
courfe alfo of the Waters? from which courfe alfo perhaps the
r> fiux a d e Et^^i^g^^^^ flowing may come, by reafon of the different fcitu-
flZ ma/depTd atiou of the Tcrreftrial Shores : againft which the Water coming
tmrhediMrftMi mo-^ to bcat, may alfo rctum backwards with a contrary motion, lik^
noH of Heaven. experience flieweth us in the courfe of Rivers ^ for according as
the Water in the unevennefs of the Banks, meeteth with fom^
jparts that ftaiid out, or make with their Meanders fome Reach ot
Bay, here the Water turneth again, and is feen to retreat back
a confiderable fpace. Upon this I hold , That of thofe cSc&^
from which you argue the Earths mobility , and alledge it a
caufe of them, there may be affigned a caufe fufficiently valid,
reuhiing the Earth ftedfaft , and reftoring the mobility
Heaven.

S A I. V. It cannot be dcnied,but that your difcourfc is ingenious?
& ha^ttjuuch of probability?! mean probability in appearance,but
not in. .jrealky &c exiftence: It conlifteth of two parts:In the firft it

aflignef

D I A L O G U f . IV.

Jffignes a rcalon of the continual motion of the Eaftern Windc)
and alfo of a iike motion in the Watec. In the li:cond, It wfiald
draw from the fame Sourfe the caufe of tlie Ebbing aud Fbwiug.
The lirft part hath ( as i have faid)fome appearauce of probabi-
lity 5 but yet c^treamly Ids then thaif . which .w.e lake from th^
Terteftrial nwtion. Thefccondis notimeiy wboUjy uvfrobtbh,
feut akogether impoffible and falfe. And coming to the .iirft,
w'hfereasitiMaidthat the Concave vofaiie Moon cairleth ;*bout
tHe element of Fire, and the whole Air, even to the tops of the
Jiiglwr Mountains. I anfwer tirft, that it is duhwus whether
there be any element of Fire : But fuppoie there be, it is much
doubted of the Orbe of the Moon,iisalfoof allthercft ; thait is,
Whether there be any fuoh folid bodies and vail, or cUsjWlictlier
^^ond the Air there be extended a continuate expantion of a
fubftance of much more tenuity and purity thanour Air, up and
^oWn which the Planets go wandring, as now at laft a good past
ofthofc very Phylofophers begin co think : But be it in this or mi
that manner, there is no reafon for which the Fire, by a fimple
contraft to a'fBperficies.whichyouyam- ielf grant to be bnooth
andtcrfe (hould be according to its whole depth carried round «a
a motion different from its natural inclination ; as haoh beeii.de-
fijfely proved,and with fenfiWe reafons demonftrated by^ ll Sagr
tiatore: Befides the other improbability of the iajid motioxis
transfufing kielf from the fubttleft Fire throughout tiie Air^uch
more dcnfci and from that alfo again to the Water. But that
4body ofTuagcd and niountainous lurface, by revolving io it
f«*€, fcoHld carry with it the Air contiguous to it , and agauift
which its ptomontarics beat, is not onely probable but nedeffary,
and experience thereof may be daily iie«i though withouic fee-
"igit,l believe tliat there is no )u«igement that doubts th£««»J
Ano the other part, fuppofing that the motion of Heaven did
'^iVry round the Ait, and alfo the Water; yet would that motioa
fi>r,H that have noting to do with the Ebbing and Flowing,
for being that from one oncly and uniform caufe, there can tol-
low but Inc fole and uniform effea i that which #ould be dil^-
*«*4 in the Water, would be a continuate and unitom. «>unc
fromtai to W<^ft \ -d in that a Sea onely, wh^h run„ing.om.
P»fs environeth the whole GE6be. B«Mnietermin^ Inch
^^HtheMediteY^arieftut upm^hetaft, tha?H^ld^^
motion. For if its Water might be driven by the^le of
Hcartn towards che Weft , it would have W dry wantages

: Befides that our Water runneth f ^«"^y JXt^
Weft, But returnethbackwa ds towards the£*ft, and ttettrf^oK
flinaiPwiods • And whereas you fay by the -cicampk ef Kiva^,
tlttt thOuRh the courfe of the Sea Werfc Originally ^iX 'Of^

405-

A redfyn of the
continual MCt">*>of
the Mr and W*'
ur may ^' f
m0ktnlthe Earth
i.jove-^lf'i then tj

able.

Itsitnprobuhlrthat
the element ofFire
jhould he cArriecL
round hj the Con-
cave of the Moon,

* A Treatifc of our
Anchor formerly
ciccd.

The Lkifing and
Flowing cannot der
fend on the motion
of Htaven^

G. Gal I l e n sv hi^ Sjjleme.

from Eaft to Weft, yet neverthelefs the different Pofition of the
Shores may make part of the M^ater regurgitate, and return
backwards: 1 grant it you, but it is neceflary that you take no-
tice my SimplictH^^ that where the Water upon that account
returneth backwards, it doth fo there perpetually ^ and where
it runneth ftraight forwards, it runneth there alwaycs in thelatnc
manner^ for fo the example of the Rivers fhewes you: But in the
cafe of the ebbing and flowing, you muft finde and give us iome
reafonwhy itdothin thefelf fame place, run one while onewayj
and another while another^Effeds that being contrary & irregular,
can never be deduced from any uniform and conftant Caule *
Andthi^ Argu|aent, that overthrows the Hypothefis of the mO'
tion contributdsd to the Sea from the Heavens diurnal motiofl?
doth alfo confute that Pofition of thofe who would admit the (ok
diurnal motion:pf the Earth , and believe that they are able with
that alone tcr gi^ea reafon of the Flux and Reflux : Of which
efFeft finceit isirrcgularjthecaufemuft ofneceflity be irregular
and alterable.

S I M p. 1 have nothing to reply, neither of my own, by reafon
of the weaknefs of my underftanding j nor of that of others , lot
that the Opinion is fo new : But I could believe that if it ^^^^
fpread amongft the Schools, there would not want

Phylofophers

able to oppofe it.

S a gr. Expcft fuch an occafion ^ and we in the mean tiine
if it feem good to Sal^iattfS^ will proceed forward.

S A L v. All that which hath been faid hitherto , pertaineth
the diurnal period of the ebbing and flowing^of which we havei^^
the firft place demonftrated in general the primary and univerfa^
Caufc , without which, no fuch efFed would follow : Afterw
pafling to the particular Accidents^ various, and in a certain fort
irregular,that are obferved therein : We have handled the fecon-
dary and concommitant Caufes upon which they depend. NoW
follow the two other Periods, Monethly, and Annual , which do
not bring with them new and different Accidents , other than
thofe already confideredin the diurnal Period i but they ope-
rate on the fame Accidents, by rendring them greater andleffef
infeveral parts of the Lunar Moneth, and in feveral times ol
the Solar Year 5 as if that the Moon and Sun did each conce^^^
it felf apart in operating and producing of thofe EfFefts j a thing
thattotallyclaflieth withmy underftanding, which feeing
that this of Seas is a local and fenfible motion , made in an
menfe mafs of Water, it cannot be brought to fubfcrib^ |^
V^bts, to temperate Heats, to predominacies by occult Quali'
ties,^nclt^j f^^j^ like vain Imaginations, that are fo far from be-
ing, or bemg poffible to be Caufes of the Tide i that on tbe con-
trary

Dialogue. 1 V.

trary, the Tide is the caufc of them, that is, of bringing them
into the brains more apt for loquacity and oftentation, than for
Ae fpeculation and difcovering of the more abftrufe fee rets of
Nature-, which kind of people, before they can be brought to
Prononnce that wile, ingenious, and modeft fentence, / k^ow it
^ot^ fuffer to cfcape from their mouths and pens all manner of ex-
travagancies. And the onely obferving, that the fame Moon, and
^l^e fame Sun operate not with their light With their motion,witb
great heat, or with temperate, on the IclTer reeeptacUs of Water,
but that to effcft their flowing by heat, they muft be reduced to
Httle leffe than boiling, and in (hort, we not being able artificially
^ imitate any way the motions of the Tide, fave only by the mo-
tion of the Veffel, ought it not to fatisfie every one, that all
*e other things alledged , as caufes of thofe eflefts , are
vaine fancies, and altogether eftranged from the Truth. I
%5 therefore, that if it be true, thar of one efFefl: there is but
One folc primary caufe, and that between the caufe and efFea,
there is a firm and conftant connexion j ic is neccffary that when-
foever there is feen a firm and conftant alteration in the cfFed,
there be a firm and conftant alteratfon in the caufe. And be-
Caufe the alterations that happen in the ebbing and flowing in
feveral parts of the Year and Moneths, have their periods firm and
conftant, it is neceffary to fay, that a regular alteration in thofe
fame times happeneth in the ptimaiy caufe of the ebbings and
flowings. And as for the alteration that in thofe times happens
in the ebbings and flowings confifteth onely in their greatnefsi
that is, in the Waters rifing and: falling more or leffe, and in
running with greater or leffe impetus j therefore it is neccffary,
that that wliich is the primary caufe of the ebbing and flowing^
doth in thofe fame determinate times incrcafe and diminifli its
We. But we have already concluded upon the inequality and
irregularity of the motion of the Veffels containing the Water to
l>cthe primary caufe of the ebbings and flowings. Therefore
it isneceffary, that that irregularity, from time to time, corre-
fpondently grow more irregular, that is, grow greater and leffer.
Now it is requifitc, that we call to minde, that the irreguUnty,
^•^*tis,the-.different velocity of the motions of the Veilels , to
^it. of the parts of the Terreftrial Superficies , dependeth on
^Wmovin/with a compound motion, reful ting from the com^
Mixtion of the two motions, Annual and Diurnal, proper to the
^holc Terreftrial Globe i of which the Diurnal converfion,by
while adding to, and another while fubftradrng from , the
A^^ual motion, is that which produceth the irregularity in the
compound motion fo that, in the additions and lubftraftions,
the Diurnal revolution make th from .the Annual moii^^n,

cdn-

4o'7

Th d/terathni
in the effe^s argue
alteratisu in the

The caufes at
Urge agigneX of
the Tzf$cds M9'
nethlj and Annw,
al ef the ehbinis
avd flojringt.

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2°K.B. 9,163

^o8 Gaul ^usy his Syjieme.

confifteth the original caufc of the irregular motion of the Vef-
The momhiy fels, and confeqiieHtly of the Ebbing and Flowing : inlbmuch
7iiZrht!dl7n ^^^^ ^^^^^ additions and fubftraftionij fliould alwayesi proceed
dlpJdJpon 'IT- in the fame proportion, in refpeS of the Annual motion, the
thtmg^faveon the caulc of the Ebbing and Flowing would indeed continue , but
^Iddi^ilm & [hL y fo as that they would perpetually return in the fclf lariic man-
ftr^atons of the ner : But we are to finde oat the caufeof making the lame Eb*
bings and Flowings in divers times greater and lelTer : There-
fore we muft (if we will retain the identity of the caufe) find the
alteration in thefe addicions and fubftra&ions , that make theitt
more Sc Icfs potent/ui producing chofc effeds which depend there-
upon. But I lee not how that potency and hnpotence can be intro-
duced, unlelTe by making the fame additions and fubftraftions^
one while greater, and another while leiTer ; fo that the accelera-
tion and the retardment of the compound motion? may be m<ide)
fometimes in gi eater, and fometimes inleffer proportion.

S A G jifc I feel my fclf very gently led, as it were, by the hafld>
and though I finde no rubs in the way, yet nevertheleffe^ Ji''^ *
blind mani, I lee not whether your Clue leadeth me, nor can 1
hnaginc where fuch a Journey will end.

Sal v. Though there be a great difference between my
pac*t Philofophyj and your more nimble Reafon, yet neverthCi^
le^^e, in this particular which we are now ii|)on, I do not inuCft
wonder, if the apprehcnfiveneffe of your wit be a little oblcU-
red by the dark and thick mill that hides the mark, at which
aime : and that which kffeneth my admiration is, the remeXtt*
brance of the many hours, many dayes, yea more, many nigW*
thatHiave confumed in this contemplation, and of the many
times that, defpairing ro bring it to a period, I have, for an in-
couragemcnt ot my fclf, indeavoured to believe, by the exam*
|>!e ot the unfortunate Or/vt»tf?<?, that that might not poflibly be
true, which yet the teftimoay of fo many credible men fct be*
foiC my eyes : wonder not, therefore, if this once, contrary
your cuftome, you do not forefce what I intend : and if you wiU
needs aidmire, I believe that the event, as far as I can )udge nn^
expected, will make you ceafe your wonderment.

S A G R. I thank God, that he did not permit that defperatf^J^
of yours to end in the Lxit that is fabled of the ^^^^^^^^^f^^
lando^ nor in that which haply is no leife fabuloufly related «
AnjiotU^ ^ that fo neither my felf nor others fliould be deprive®
of the difcovery of a thing, as abftrufe as it was defirable 5
bcfecch you, therefore, to fatisfic my eager appetite as ^^^^ ^

S A L 1 am ready to lerve you : We Were upon an ^^^^t^

in what inann^r the additions and fubftraftions of the Terreit"^

all

Dialogue IV',

all converfion from the Annual mocion, could be made , one
while in a greater, and another while in a IclTer proportion,
whichdivcrtity, and np other thing, could be afligned tor the
entire of the.aiteration$:j Monethly aiid Annual, that are feen ia
the greiitnetie of the Ebbings and Flowings. I will now con-
fer how this prqpbrtion of the additions and fubftra&on? of ^^^^^ ^^^^^
the Diurnal Revolution, and Atnuial motion may grow greater ^uermg the fro-
5ind leffer three feveral wayes. One is by inpreafing aad dimi- ^^i/^^^
mfliing the v<- Jocity of the Annual motion, retaining the additi-
ons and fMbftraaions made by the Dinrnal converfion in the tu anr.ud mo-Aon.
fame 'greatnelTe, bec.a^ie the Annual, motion being about three
limes greater, that is, more velocious than the Diurnal motion
(coniidered likcwifc in the Grand Circle J) if we increale it
^ntiw , the , additions and fubftraaions of the Diurnal motion
WSl occafion lefle alteration therein : but, on the other fide,
"iaking it more flow, it will be altered in greater proportion, by
^hat fame diurnal tnptipn, )uft as the adding or fubftrafting
four degrees of velocity from one that moveth with twenty de-
grees, alt^reth his courfe leffe, than thofe very four degrees would
dp, added or fubftrafied from one that fliould move onely with
ten degrees. The fecond way would be, by making the additi-
ons and fubftraaioas greater and leffer, retaining the annual mo-
tion in the fame velocity v whigh i§ as eafie to be underftopd^as it
is manifeftjthat a velocity ^.gr. of :io. degr.is more altered by the
iuidition or fubftraaionof lo.deg.than by the addition or fubftra-.
ftion of 4.The third yvay would be,in cafe thete two were joyned
together,diminifliing the annual motion>& increafing the diurnal
additions, and fubUraaiom. Hitherto , as ypu fee , it was no
hard matter to attain, feuj: yet it proved tome very hard to find
what means this might be effefte^ in Nature. Yet in tte end.

That yihtrU ti

I findc that (he doth admirably make ufe thereof, and in wayes muM,.n.^
«lmoft incredible : 1 mean, admirable andmcredible to us, but j^'^„„\^f„
not to her, who woiketh even thofe very things, which , to our
capacity, are of infinite wonder, with extraordinary facihty and
fimplicit'y : and that which it is hard for us to underftand, is ea-.
fieior her to efFea. Now to proceed, having ftewn that the
proportion bet\yeen the additions and fubttraSions of the Diur-
nal converfionand Annual motion may be made greater and lei-
fcr, two wayes, Cand I fay two, becaufc the third is comprized in

^i^^l alterations. That of the Monethly Period would ceafe, if
the annual motion fhould not alter. And m cafe the additions
^nd fubftraaions of the diurnal revolution ftiould Continually

Fff be

// the 'Diulrnd
motion ihonU >*ot
alter y the annual
Period vfMccsft

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2°K.B. 9,163

4ic

G.tj

A L I L ^ U

erne.

The irne Hypom
thefts mAj difcdtch
its revolutiom in a
Jhorter ttme , tn
Ujfer circUs than
in greater ;
which u fr^'vc^''^

The firfi ex-

be^qual 5 the alterations of the annual Period would fail

Sagr. It feemsthcn, that the Monerhly alteration of eb-
bings and flowings dependeth on the alteration of the annual
motion of the Earth ? And the annual alteration of thofe eb-
bings and flowings do, it feems , depend on the additions an
fubftraftions of the diurnal converfion ? And here now 1 finae
my felf worfe puzzled than before , and more out of hope o
being able to comprehend how this intricacy may be, which
more inextricable^ in my judgment, than the Gordian knot. An
I envy ^imflicius^ from whofe fiience I argue that he doth ap-
prehend the whole bufineffe , and is acquit of that confunon
which greatly puzzle th my brains*

S IMF* I believe verily, SagredtfS^ that you arc put to a
a ftand *, and I believe that 1 know alfo the caufe of your con-
fufion, which, if I miftake not, rifeth from your underftanding
part of thofe particulars but even now alledged by Salmatff^^
and but a part. It is true likewife that I find my lelf free from the
like confufion , but not for that caufe as you think , to wit, b^'
caufe I apprehend the whole, nay it happens upon the quite
contrary account ^ namely , from my not comprehending anjr
thing ^ and confufion is m the plurality of things , and not in
nothing. ,

Sagr. You fee Sdviatp^^ how a few checks given to Si/^f"'
cius in the dayes preceding , have rendered him gentle , an
brought him from the capriol to the amhle. But I befecchjo^
without farther delay, put us both out of fufpence.

Sal v. I will endeavour it to the utmoft of my harfli way
cxpreffing my felf , the obtufenelTe of which, the acuteneffe ot
your wit fliall fupply. The accidents of which wc are to enqni»^^
the caufes are two : The firft refpefterh the varieties that happen
in the ebbings and flowings in the Monethly Period ^ and the o-
thrrclatethtothe Annual. Wc will firft fpeak of the Monctn-
ly , and then treat of the Annual ; and it is convenient thar w
refolvc them all according to the Fundamentals and Hypo^heU
already laid down , without introducing any novelty either in A*
ftronomy,or in the Univerlc , in favour of the ebbings and floW^
ings j therefore let us demonftrate that of all the fevcral acci-
dents in them obferved , the caufes refide in the things alrca J
known , and received for true and undoubted. I fay therefore?
that it is a truly natural^yea neccfTarj thing, that one and theianii^
moveable made to move round by the fame moving virtue in ^
longer time , do make its courfe by a greater circle , rather t
by a IcfTcr and this is a truth received by all , and co^
firmed by all experiments , of which we will produce a te^'
In the wheeUdocks , and particularly in the great ones , ^^^^tc

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2°K.B. 9,163

DlALOGUf. iV.

4tt

kmflt.

derate tlic rime , the Artificfrs that make them accomodate a ccr-
volubte. .ftaffe horozontally , and at each end of it they ta-
fteiv two Wc'fohts of Lead , and when the time goeth too Oow,
by the oi^ely : removing thofe Leads a little nearer to the centre
<^'theftaffe ^ they render its vibrations more frequent i and on
thfe conrrarv/to retnW it , it is but drawing thofe Weights more
li^wards the ends ; for fo the vibrations are. made more Mdome,
aftd confeqtfeivtly thd intervals of sh<r hours are prolonged.
^ Here eh^',ttoVcnt^Vc«de is the fkme , name y the counterpo.fe,
^ moveables are' thblfc; fime Weights of lead , and their vi-.
bratiohs a,^ more frc(?aent whcn.they ate : ecQtcr to tlie centre,
that is I when thcv imove by kffer cirdes;; Hanging equal
Weiaht^^at Wnemial o»rdt , and beingirerodvpd ffoni their per-
pendicularity , iettin^them go y we Ojall ke thofe that are pen-
dant at the (horter cords , to make their vibrations under ftorter
times, as Hiofc that moie by l?fli;r circles. Again , let lucha
kind of Weiiiht be faftcne'd to a cord , which cord let play, upon
a ftaple faftencdin the Seeling, and dp you hold the othfirend
<jf the cord .« your hand:, and having given^the motion to the
pendent Weight , whilft it is making its V'brat.ons, puU the
endofthecordthat you hold m your hand, fo that the. Weight
may rife higher and higher : In its rifing you ftall lec the fre-
quency of its vibrations encreafe , m regard that they^ar?! made
Lccffively bv leifer and leiTer circies. And here I defire you to
take notice of two particulars worthy to beobfervcd. One is
that the vibrations of one of thofe plummets are made witt^ iuch ,*„>„fc-««w.
a necefficy under luch determinate times , that it is altogether
impoflible to caufethem to be made under other tinies , '""^fle
it be by prolonging , . or abrcviating the cord i of which you
may alfo at this very inftant arcercain your felvesby exper.ence,
tyiig a ftone to a -pck-threed , and hiding ^he other end in
yourhand , trying rhether you can everby any artifice be ab e
. ' • other than one determinate

fwmg it this way and that way tn otner tiwi _
time , unleflc by lengthening or Oiortening ; the ftring , which
you find to be abfolutely ImpoQible The other particular
^.ruly admi." ble is , that the felf famef c,«i«/.^ -kes
t~ns ^ith one and the fame frequency , ry httle an^as t
^ereinfenfibly different, whether they ^made by^^LS

very G^all archesof the felf-fame circumference. I mean that

Whethltremovethe ^«^«/- f-P-P^'^-^^^
«t three decrees onely or whether we remove it 70. »o. nay to
'■^^nti e S"ant itbeingletgo, will in the one cafe and. a
other Ike its'vibrationswidi the fame frequency , as well
»he former where it is to move by an arch of but four or fix dc-
«fees, anhefccond, ^heic it is^ppaffe arches ot 160. or pio^

Tim yirtkidir

12.

Admirable Tro'
blcmi of movea-
bles Aefcendtng by
the QudArjfit of a
Circle y^ndoftja^fe
dtfctndtng by mU
the cords of the
whole Circle,

G. G A L I L A u s , his Syjleme.

degrees. Which may the better be fein, by hanging two weights
at two firings of equal length, and then removing them from per-
pendicalarity^one a Itttk way, and the other very far the which
being fet at liberty ,will go & return under the fame times,the one
by arches v^ry fmall,& the other by very great ones, from whence
followeth the conclufion of an admirable Problem y which is.
That a Quadrant of a Circle being given (take a little diagram ot
the fame, [in Fig. 3 ] ) as for inftance : A- B cred to the Hori-
zon, fa as that it reft upon the plain touching in the point B-
an Arch being made with a Hoop well plained and fmoothed m
the concave part, bending it according to the arrvity of the Cir*^
cumference A D B. So that a Bullet very round and fmooth
may freely run to and again within it (the rim of a Sieve is very
proper for the experiment) I fay, that the Bullet being put in any
whatever place, neer or far from the loweft term B. As for in-
fkance, putting it in the point or here in D, or ia p*3 and then
let go, it will in equal times, or infenfibly different arrive at the
term Bj departing from C, or from D, or from E, or from what-
ever other place i an accident truly wonderfuU. We may ad
another accident nolefs ftrange than this, which is, That more^
over by all the cords drawn from the point B to the points
D, Ej and to any other whatfoever, taken not onely in the QP^"
drant B A, but in all the whole circumference of the Circle tnc
faid moveable (hall defcend in times abfolutely equal infomucli
that it (hall be no longer in dcfcending by the whole Diameter
ercft perpendicularly upon the point B, then it fliall in defcend'
ing by B. C although it do fublend but one fole degree, or a le^'
fer Arch. Let us add the other wonder, which is. That the i«o-
tions of the falling bodies made by the Arches of the Quadrant
A B j are made in fliorter times than thofe that are made by th^
cords ofj thofe fame Arches j fo that the fwifteft motion, and
made by a moveable in the fliorteft time, to arrive from the
point A, to the term B, fliall be that which is made, not by the
right line A,B, (although it be the fliorteft of all thofe that cao
dc drawn between the points A. B. ) but by the circumfcreivce
A D B. And any point oeing taken in the faid Arch as
eyampk : The point D. and two cords drawn A D, and D- ^
the moveable departing from the qoint A, fliall in a lefs
come to B, moving by the two cords A D and D B. than by ^ ^
fole cord A, B. But the fliorteft of all the times fliall be chat o
the fa)l by the Arch A D B. And the felf fame accidents ar
to be underftood of all the other lefler Arches taken fro^^^ ^
Wermoft term B. upwards. _

^^GR. No more, no more ; for you fo confund and fill
with Wx>ndfeps, anddiAjrafl: jpy thoughts fo many feveral '

Dialogue

IV.

4'j

t«»at I fear I ftiall have but a fmall part of it left free and difih^

matter

: even

treated

""•■-noritieii IS i'i»>-'-»'-" " intricate; So that

I'intTcat' you'tavouchrafe mc" hiving once difpatcht the bufineft
•of the ebbinss and flowings, to do this honoar to my houfc Qand
yours) fome other dayes, and to difcourfe upon the f^ many other
ProblL that we have left in lufpence > and which perhaps arc
no lefsTurious and admirable, than this that hath been d.fcuffed
thefe dayes paft , and that now ought to draw to . con-

'^"s!"' V I (liall be ready to ferve you, but we muft make more
thanoneor woSeffions 'ifbefides the other q-ft-- -^^^^ff
to be handled apart, we would dilcai^: thofe many th t per tarn
to the local monon, as well of natnral moveables ^^^^^^^^^^^
ed- an Aieument largely treated of by our Lynceati Accade-
B^STningtoUrfirft purpoie where wewere about to
declare That the bodies moving circularly by a movent virtue,
ueciare, m^t^ remaineth the fame, the times of the circula-
"^"Z^ll ^^^^^^^^^ impoffibletobe made
r 'Xter having given examples, and produced cxperi-
longer or mortem hav-^^g^^^^ confirm the lame

rrbVthe'x^^^^^^^^^^^^

:,thicrwe L'the fame rule oblerve^^ -veby
later Circles, conHrm longer times ,n paffing them A moft
Ecntobfemtionof thiswe have horn the Me^,c^.« Pla-
nets, which in (hort times make their revolutions about THfiter
Infomuch that it is not to be queftioned, nay we ^^^J ^ .
fure and certain, that if for example, the '^^""^Tg;"^^
movedby the fame movent faculty, ihould retire by li tie and

UtfU- 1 <r^r r;rrles it would acquire a power of abreViating
little m icffer Circles , it wo n fendnlnm, of which in
the times of its Periods according '^ 'J^' f^^^^^^^ ^e cord, that
the courfe of its vibrations, we J-g^^« ^^^^^^ ^y it paffed.

Know now that tms tnai i u | pt ns call to mind>

Moon, is feen and verified clfennally in fe^^^^

thaf it V„,K hfen already concluded by us, togetner wu ^ The^rtbi^,.

tnat It hath been ^"'"'^ ^ feoaratc the Moon from the Earth, „^^^tionif ,ht

*«*,Thatitisnotpo{ribletoleparatc ^ Let us ^c/.,,fct,»«W

about which it without difpute revo^veth ^^^^ , J

remember alio that the Terreftrial Globe accomp y^ J ^^,^„.,.

bytheMoon,goethalongth2--f-^^^^^

about the Sun in a year, in "^^l^^^^^ ,evol-tion it follow-

Je Earthalmoft thirteen t.^^^^^^ near the Sun •, thatis,

S''^"^*^'["^^''Vhe nd the Earth, and fometimes

When „ is between the S^n an^ ^^^^^^ ^

^uchmore remote , that is, wucu ^

the Moon and Sun ; neer, in a word , at the time of its conjun
fiion and change 5 remote, in its Full and Oppofition i and the
greatcft vicinity differ the quantity of the Diameter t>f the Lu-
nar Orb. Now if it be true that; the virtue which moveth the
Earth and Moon , about the^Sun , be alwayes maintained .in
the fame, vigour and if it be true tha.5 the fame, moveable
moved by the fame viirtuc , but in circles ,iuiecjual , do in fliorter
times paffe like arches of leffer circles , it ^uft needs be granted^
that thp Moon when it is at a Ifffe diflance'from the Sun , that is
in the time of conjunfiion , paffeth greater arches of the Grand
Orb^than when it is at a greater diftance, that is in its Opppfition
and Full. And thisTunar inequality muft of nccefTity be imparted
to the Earth alfojfor if we (hall fuppofe a right line produced from
the centre of the Sun by the centre of the Terreftrial Globe, and
prolonged as far as the Orb of the Moon ^ this (hall be the ferni*
diameter of the Grand Orb , in which the Earth, in cafe it were
alone, would move uniformly, but if in the fame femidiauieter we
fliouJd place another body to be carried about , placing it one
while between the Earth and Sun, and another while beyond
the Eartl^ , at a greater diftance from the Sun , it is ncceflary,
that in thisfecond cafe the motion common to both, according
to the circumference of the great Orb by means of the diftanc e
of the Moon, do prove a little flower than in the other cafe,
when the Moon is between the Earth and Sun , that is at a leffer
diftance. So that in this bufinefTc the very fame happeneth that
befals kn the time of the clock i that lead which is placed one
while farther from the centre , to make the vibrations of the
ftafFe or ballance lefle frequent , and another while nearer , to
make them thicker, reprefcnting the Moon. Hence it may b^
manifeft , that the annual motion of the Earth in the Grand
Orb , and under the Ecliptick , is not uniform , and that its ir-
regularity proceedeth from the Moon , and hath its Monethly
Periods and Returns. And becaufe it hath been concluded, that
the Monethly and Annual Periodick alterations of the ebbings
and Rowings , cannot be deduced from any other caufe than
from the altered proportion between the annual motion and the
additions and fubftra£iions of the diurnal convcrfion ^ and that
thofe alterations might be made two wayes j that is by altering
the annual motion , keeping the quantity of the additions un-
altered , or by changing of the bigneffe of thefe , retejning
uniformity of annual motion. We have already found the firft
of thefe , depending on the irregularity of the annual motion
occafionedby the Moon , and which hath its Monethly Periods.
It IS therefore neceffary , that upon that account the ebbings
andflowings have a Monethly Period in which they do groVv^

greater

Dialogue. iV. 4*1

grcatetandlcffcr. No^V youfee thatthc caufc of the MonetWy
Period ref.dcth in the annual motion ^ and withal you fee how
much the Moon is concerned in this bufinefs, and how ,t is there
With interrupted apart,without having any thing to do with either,
WithScasor Wateis. . ,

S A G R. If one that never had ken any knvde of Stairs or La-
der, were Oiewed a very high Tower and asked ,f ever he hoped
to climb to the top of it, 1 verily believe that he would anfwcr he
did not, not conceiving how one (hould come thither any way
except by flying but (hewing h.m a (tone of but a foot high and
^aWmghLihSLer he thought he could get to the top of that
Um certain that he would anfwer he could, and farther, that he
would notdeny,but that it was not onely one, but t^n'/wenty,
»nd an hundred times eader to climb that : But "ow ?f heihould
befhewed the Stairs, by means whereof, with the facility ^by h«n
granted, it is poQlble to get thither, whither he a little before had
»fi5rmed it was impoffible to afcend, 1 do think that laughing at
himfcif hewould confefshisdulnefs cf apprehenfion. Thus
S^hiatus haveyouftepbyfteplogently lead me that not

. . r ' . \ rin,4e that I am got with fmall piins to that
without wonder, I hndc tnat i am g i. r
beiaht which i dcfpaircd of arriving at. Ti:. true, that ttie btair
SSng been dark, 1 did not perceive that I was got nearer
to or arrived at the top, till that coming into the open Air I dif-
covered a great Sea, and fpacious Country : And as in afcending
one ftep, there is no labour ; fo each of your propofilions by it
felf feemed to me fo plain, that thinkingl heard but little or no-
ihtne that was new unto me, 1 conceived that my benefit thereby
i«dbeen little or none at all : Whereupon I was the mdre ama-
zed at theunexpeaed ex,t of this difcourfe that hath guided me
to the knowledge of a thing which 1 held impoffible to be de-

tlStions, thofe irregularities ought to have been obj^rved and «
ken notice of by Mronomcrs, which I do not know ^^at they
-e : Thrforll piay who are better acjua^^^^^^^^^^
*ings than I, to free the from this doubt , and ten ra

" S ^Tt^on ask a rational queftion, and anfwering to the Ob-
. salv. Youasfcarai ? Aamnlmv in the courles of many „4fr«i.«««7rt
)ea.on,lfay, That although ^^ .« «^^^^^^^^ the conftitution "^^frvU^M
ages hath made ^ g-j/^JJ^^^ hitherto atrived

haply m3^^^^^^ Itis tobefuppofed thatthe

firftobTrversofHeavenkneWnomorebutone motion common

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4i5

G. G

AL IL^US

his Syfieme.
yet I believe that in feW

Sarurn/#r its

cury fgr its rare-
fiefs . of appeartnff^
were among thofe
that were Ufioh-
ferved.

Particular f^ru-
^ttres of the Orhs
of the Planets not
jet veil refolved.

The Snn faff-
ethone half of the
Zodiaek.ntnt dajs
fioner than the
•thfr.

The Croons mo-
tion principally
foHght tn the ac-
eoHfit 6f iclifftsh

to all the Starsj as is this diurnal one

dayes they perceived that the Moon was inconftant in keeping
company with the other St irs . but yet withal, that many yc^^s
paft,betore that they diftinguiflied all the Planets : And in par-
ticular,! conceit that Saturn by its flownefs , and Mzrcury by i'^^"
lon of its I'eldom appearing, were the laft^hat were obfervedto
bewandiing and errant. It is to be thought that many more
years run out before the ftatioi s and retrogradations of the three
luperiour Planets were known, asalfo their approximations and
rcceffions from the Earthaneccflary occafions of introducing the
Eccentrix and Epicicles, things unknown even to Arijtolle fio^
that he makes no mention thereof. Mercury^ and Veiius^ with
their admirable apparitions , how long did they keep Aftrono^
mcrs in fufpence, before that they could refolve (not to fpeak of
any orlier of their qualities) upon their fituation ? Inlomiich
that the very order oncly of the Mundane bodies, and the inte-
gral ftrudure of the parts of the Univerfe by us known, hath been'
doubted of until] the time of CopcrmcHSj who hath at laft given
us notice the true cpnftitution-, and real fyftemc, according to
which thofc parts are dilpoied ^ fo that at length we are certain
thn Mercury , Vems j and the other Planets do revolve about
the Sun , and that the Moon revolveth about the Earth. But
how each Planet governeth it felf in its particular revolution,and
how precifely the ftruSure of its Qrb is framed^ which is that
which is vulgarly called the Theory of the Flanets^ we cannot a5
yet undoubtedly refolve. Marsj that hath fo much puzJed our
Modern Aftronomers, is a proof of this ; And to the Moon her
felf there have been alligned feveral Theories, after that the fai^l
Copevmus had much altered it from that of Ftolomy. And %9
defcci^ to our particular cafe, that is tq fay, to the apparent mo-
tion of the Sun and Moon , touch ing the former, there hath been
obferved.a certain great irregularity, whereby it paffeth the two
femicircies of the Ecliptick, divided by the points of the Equi-
noxes in very different times ^ in pafling one of which, it fpend-
eth about, nine dayes more than in pafling the other j a difference,
as you fee, very great and notable. But if in pafling fmall archesi
fuch for ex4mple as are the twelve Signs, he maintain a moft re-
gular motion, or elfc* proceed with paces, one while a little more
fwift, and another more flow, as it is nccefTary that it dojin cafe
the annual motion belong to the Sun onely in appearance ,
in reality to the Earth in company with the Moon, it is what hath
«ot hitherto been obferved, nor it may be, fought. Toucbi^ig
^hc Moon in the next place, whofe reftitutions have been pri*^"
cipally loqkt into an account of the Eclipfes, for which it is fuf-
hcient to hjive an cxa^i knowledge of its motion about the Earth?

Dialogue- IV* 4l7

i^t hath not been likewife with a perfeft curiofity inquired , what
courfe is thorow the particular arches of the Zodiack. That
therefore the Earth and Moon in running through the Zodia^l^
that is round the Grand Orb, do fomewhat accellerate at the
Moons change, and retard at its full, ought not to be doubted 5
for that the laid difference is not manifeft, which cometh to be
iinobrcrved upon two accounts , Firft, Becaufe it hath not been
lookt for. Secondly, Becaufe that its poflible ic may not be very
great. Nor is there any need that it (hould be great, for the pro-
ducing the cffeft that we fee in the alteration of the greatnefs of
ebbings and flowings. For not onely thofe alterations, but the ^^^.^^^ ^
Tides themfelves are but fmall matters in refpeft of the grandure /f^^i«^/"rr pm;
of the fubjeas on which they work j albeit that to us, and to our
'ittlenefs they feem great. For the addition or fubduftion of ^l^sLVZoftht
one degree of velocity where there are naturally 700, or 1000, velocity of the ma-
be called no great alteration, either in that which confcrreth ^"^"^jf^/^^!'"^'"
*t) or ia that Which receiveth it : the W atcr of our Mediterrane
carried about by the diurnal revolution, maketh about 700 miles
an hour (which is the motion common to the Earth and to it, and
therefore not perceptible to us)& that which we fenfibly difccrn
to be made in the ftreams or currents, is not at the rate of full one
mile an hour, (1 fpeak of the main Seas, and not of the Straights)
and this is that which altereth the firft, naturall ^ and grand mo-
tion and this motion is very great in refpeft of us, and of Ships :
for a Veffel that in a ftanding Water by the help of Oares can
make <Lf, g. three miles an hour , in that fame current will row
twice as far with the ftream as againft it : A notable difference
in the motion of the Boat, though but very fmall in the motion
<of the Sea, which is altered but its feven hundredth part. The
like I fay of its rifing, and falling one, two , or three feet 5 and
fcarcely four or five in the utmoft bounds of a ftreight two thou-
fand,or more miles lang,and where there are depths of hundreds
Qffeet^ this alteration is much Icfs than if m one ot the Boats
that bring us frefii Water, the faid Water upon the arreit ot the
fioat n^ould rife at the Prow the thicknefs of a leaf. I conclude
therefore that very fmall alterations in refpeft of the immenfe
g^-eatnefs, and extraordinary velocity of the Seas, is fufficient to
«^ake therein great mutations in relation to our fmallnels , and td

^^r accidents. . . , •

% G R. I am fully fatisfied as to this particular ; it remams to
declare unto us how thofe additions and fubftraaions derived
f^<^m the diurnal Vtrttgo are made one while greater and ano-
^^^^ while klTer ; from which alterations you hmted that the an-
nual period of the augmentations and dinunutions of the eb*
*^ings and ftowines did depend. ^

Ggg

4t8 G. G A L I L /£ u ^ix Syjieme.

The caufes of S A L V. I wiU ufe niy utmoft endeavours to render my felf
the inequaUty If intelligible, but the diJRcuIty of the accident it felf, and the
fffl/l^'aio7 f'^h attention of mind rcquifite for the comprehending of it,

MurZi *convlfion conftrains me to be obfcure. The unequalities of the additions
from the Mmai and fubfttafiions 5 that the diurnal motion makcth to or from
fnottou, annual dependcth upon the inclination of the Axis of the di-

urnal niotion upon the plane of the Grand Orb, or^ if you pleafc>
of the kcliptick *, by means of which inclination the Equinofti^l
interfe&eth the faid Ecliptick , remaining inclined and oblique
upon the fame according to the faid inchnation of Axis. And the
quantity of the additions impoFteth as much as the whole diame-
ter of the faid Equinoftial , the Earths centre being at the fame
rime in the Solftitial points ^ but being out of them it importetb
leffe and bffe , according as the faid centre fucceffively approa-
cheth to the points of the Equinoxes , where thofe additions are
leiTcr than in any other places. This is the whole bufineffe , but
wrapt up ill the obfcurity that you fed-

S A G ft. Rather in that which 1 do no not fee ^ for hitherto I
comprehend nothing at all.

S aA V. i have already foretold it. NevertheleiTe we will try
wbcthei by drawing a Diagram thereof , we can give foine
fmall light to the fame ^ though indeed it might better be let
forth by folid bodies than by bare Schemes ^ yet we will help ouf
fe Ives with Perfpective and fore-fliortning. Let us draw there-
fore , as before , the circumference of the Grand Orb, [^asi^
Fig* 4.3 in which the point A is underftopd to be one of the
SalfticiaJs , and the diameter A P the common Seftion of the
Solftitial Colure , and of the plane of the Grand Orb or Eclip-
tick J and in that fame point A let us fuppofe the centre of the
Tcrreftrial Globe to be placed , the Axis of which CAB, in-
dmcd upon the Plane of the Grand Orb, falleth on the plane of
the faid Coiure thatpaffeth thorow both the Axis of the Equino-
fiial, and of the Ecliptick. And for to prevent confufion,
us only draw the EquinofliaJ circle, marking it with thefe chara-
ftcrs D G E F, the common feftion of which, with the plane 01
the grand Orb, let be the line DE, fo that half of the faid E'
quinoaial D F E will remain inclined below the plane of
Grand Orb, and the other half D G E elevated above, f
now the Revolution of the faid Equinoftial be made, accofdii^g
to the order of the points D G E Fj and the motion of the cen-
tre from A towards E. And becaufe the centre of the E^r^n
heingin A,the Axis C B (which is ereft upon the diameter o
^he Equinoffiial D E) falleth, as hath been faid , in the Solft^^
tial Colore , the common Seftion of which and of J^he

Grand Orb , is the diameter P A , the faid line P A ih^^^

Dialogue IV^

l>e perpendicular to the fame D by reafon that the Colure is
creQ: upon the grand Orb ^ and therefore the faid D E,
fliall be the Tangent of the grand Orb in the point A.
So that in this Pofition the motion of the Centre by the arch
A E 5 that is, of one degree every day diftereth very little i yea,
is as if it were made by the Tangent DAE. And becaufe by
iweans of the diurnal motion the point D, carried about by G,
^nto E, encreafeth the motion of the Centre moved almoft in the
^^niie line D E, as much as the whole diameter D E amounts
^nto j and on the other fide diminiflieth as much , moving about
the bther femicirclc E F D. The additions and fubduftions
in this place therefore, that is in the tinie of the folfticc , fliall be
^eafured by the whole diameter D E.

Let us in the next place enquire, Whether they Be of the fame
l^ignefs in the times of the Equinoxes ^ and tranfporting the
Centre of the Earth to the point I5 diftant a Quadrant of a
Circle from the point A. Let us fuppofc the faid Equlnodial
to be G E F D, its common fedion with the grand Orb D E, the
Axis with the fame inclination C Bj but the Tangent of the grand
Orb in the point I (hall be no longer D E , but anocher which
flhall cut that at right Angles and let it be this marked H I L,
according to which the motion of the Centre I, fliall make its pro-
grcfs, proceeding along the circumference of this grand Orb.
Now in this ftatc the Additions and Subftraftions are no longer
meafured by the diameter D E, as before was done , becaufe that
diameter not diftending it felf according to the line of the annual
"motion H rather cutting it at right angles, thofe terms D E, do
neither add nor fubftraft any thing h but the Additions andl
Subftrafidns are to be taken from that diameter that falleth
in theplanethat is errea upon the plane of the'grand Orb, and
Aat intcrfefts it according'to the line H L h which diameter in this
cafe fliall be this GF and the Adjedive, if I may fo fay, fliall
l>e that made by the point G, about the femicircle G E F, and the
Ablative fliall be the reft made by the other femicircle F DG.
Now this diameter , as not being in the fame line HL of the
^•^nual motion, but rather cutting it, as we fee in the point I, the
torn G being elevated above, and E deprelfed below the plane
^fthc grand Orb doth not determine the Additions and Sub-
ftraftions according to its whole length,but the quantity of thofe
fi'^ft ought to be taken from the part of the line H L, that is in-
^ercepted between the perpendiculars drawn upon it trom the
^^^ms G F namely, thefe two G S, and F V : So that the mea-
f"^^ of the additions is the line S V lefler then G F, or then t) E
which Was the meafurc of the additions in the Solftice A. And
fofuccefRvely^ according as the centre of the Earth (hall be cdn-

Ggg3 ffitiited

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G. G A L X L ^ us 3 MSjJlme.

fiitutcd in other points of the Quadrant A I, drawing the Tan-
gents in the faid points, and the perpndiculars upon the fame fal-
ling fiom the terms of the diameters of the Equinoflial drawn
from the errefl: planes by the faid Tangents to the plane of the
grand Orb , the parts of the faid Tangents (which lhall conti-
nually be lefTer towards the Equinoftials, and greater towards the
Solftices)fhall give us the quantities of the additions and fubftra-
ftions> How much in the next place the leaft additions differ from
the greateft, is eafie to be knownjbecaufe there is the fame dif-
ference betwixt them, as between the whole Axis or Diameter of
the Sphere, and the part thereof thai lycth between the Polar-
Circles the which is lefs than the whole diameter by very near a
twelfth part , luppofing yet that we fpeak of the additions and
fubftradiions made in the Equinoflial j but in the other Paral-
lels they are lelTerj according as their diameters do diminifli.

This is all that 1 have to fay upon this Argument^and all perhaps
that can fall under the comprehenfion of our knowledge, whlchj
as you well know, may not entertain any conclufions, favc onely
thofe that are firm and conftant, fuch as are the three kinds of Pe-
riods of the ebbings and flowings , for that they depend on caufes
that ^re invariable, fimple, and eternal. But becaufe that fe-
condary and particular caufesjable to make many alterations^ in-
termix with thefc that are the primary and univerfal , and thefe
fecondary caufes being pare of them inconftant, and not to

obferved j as for example. The alteration of Winds, and part
(though terminate and fixed) unoblcrved for their multiplicity,
as are the lengths of the Straights, their various inclinations to-
wards this or that part,the fo many and fo different depths of the
Waters, who (hall be able,unlefs after very long obfervations,and
very ci^rtain relations, to frame fo expeditious Hiftorics thercof,as
that they may fervefor Hypothefes ,and certain fuppofitio"^
fuch as will by their combinations give adequate reafons of all the
appearances, and as I may fay, Anomalie, and particular irregula-
rities that maybe difcovered in the motions of the Waters? I
will content my felf with advertifing you, that the accidental
caufes arc in nature, and are able to produce many alterations i
for the more minute obfervations , I remit them to be made by
thofe that frequent feveral Seas : and onely by way of a condu'
fion t9 this our conference, I will propofe to be confidered,hoW
that the precife times of the fluxes and refluxes do not onely hap-
pen to be altered by the length of Straights , and by the difft'
rence of depths ^ but I believe that a notable alteration may ^'^^
proceed from the comparing together of fundry tarfts of Sea,
different in grcatnefs j and in pofition, or, if you will , indina^
tion 3 ^^bkh 4ifFerence happeneth exadly here in the Adriati^K

Gulph,

Dialogue. I V.

Gulph Icffe by far than the reft of the Mediterranc,and placed in
io different an inclination, that whereas that hath its bounds that
inclofcth it on the Eaftern part, as are the Coafts of S>«<», this is
ftiut up in its more Wefterly part : and becaufe the ebbings and
flowings arc much greater towards the extremities, yea, becaule
the Seas rilin^s and fallings are there onely greateft it may pro-
bably happen that the times of Flood at V.mcc may be the time of
low Watei in the other Sea, which, as being much greater, and
diftendcd moredircaiy from Weft to Eaft, cometh m acertaia
fort to have dominion over the Adnatick: and therefore it
would be no wonder, in cafe the effeas depending on the pri..
mary caufes, fliould not hold true in the times that they ought,
and that correfpond to the periods in the Adnat,ck.. as it doth
inthereft of the Medlterrane. But thefe Particularities require
long Oblervations, which I neither have made as yet, nor fliall I
ever be able to make the.fame for the future.

S A G R You have, in my opinion, done enough m opening Us
the wav ro fo lofty a fpeculation, of which, if you had given us

^ u ,Kat itrft general Propofition that ieemeth to me to
no more than th t heft ge P^^^

Veffl~ng^^e SeaLters continuing ftedfaft , it would
be impoflible, according to the common courfe of Nature, th*«
thofe motions (hould follow in them which wc fee do followi
and that, on the other fide, granting the >fcr.bed, for o-

ther refpeas,by CofemkHS to the Terreftrial Globe, thcfe fan^
alterations ousht to enfue in the Seas, if I fay you had told us na
more, this alone in my judgment, fofar exceeds the vanities in,
troduced by fo many others , that my meet looking on them
makes me naufeate them , and 1 very much admire, that among

men of fublime that .n^v^S

not one hath ever conWaed t^e J y^^^ j^^^bi-

i!;;:fTetScTnt^^^^^^^

"°s[rr;^'.oretobe admired, th^^^^^^^^^^

thoughts of fome to refer the caufe of ^^e J^^^J^ apprehenfion,
theEarrfi, therein Ae wing a more than commo^^^

they (hould, in afterwards driving fi^ple and

t^ofide -, and all, becaufe they did no^^^^^^^^^

uniform motion, as ..gr. the t-l^ '^^^^^^^^^^^^^ j^ed an unc-

ftnal Globe, doth not fuffice, t^atthe q

yen n^otion, one while ^-^"^^^i^^^^^^ the water*

lorwVipn the motion ot the veuei^ * i
conTw wilT habituate themfelves thereto, without ever ma-
king any alteration. To fay alfo (as it is related of an ancK^

4^K

One pngle mdiQ
on of the terreflri"
al Glolfe [Hjficeth
not to prodftce the

422,

The opinion $f
Seieucus theiMa-
thematician cenf fi-
red.

Kepler is with
y^fpeSl Hamed^

Sig.Catfare Mar-
filius obferveth the
(^ertdian^ to he

G. C A L I L ^ u s his Syfteme.

Mathematician) that the motion of the Earth meeting with the
motion of the Lunar Orb, the concurrence of them occafioneth
the Ebbing and Flowing, isanablblute vanity, not onely be-
caufe it is notexpeft, nor feenhow it ihould lo happen, but the
falfity is obvious, for that the Revolution of the Earth is not con-
trary to the motion of the Moon, but is towards the fame way.
So that all that hath been hitherto faid, and imagined by others?
is, in my judgment, altogether invalid But amongft all the
famous men that have philofophated upon this admirable efteft
of Nature, 1 more wonder at Kepler than any of the reft? who
being of a free and piercing wit, and having the motion afcri-
bed to the Earth, before him, hath for all that given his ear and
affent to the Moons predominancy over the Water, and to oc-
cult properties, andfuch like trifles.

S A GR. 1 am of opinion, that to thefe more fpaculative pei*
fons the fame happened, that at prefent befalls me, namely, the
not underftanding the intricate commix tion of the three Periods
Annual, Monethly, and Diurnal j And how their caufes (hould
feem to depend on the Sun, and on the Moon, without the Suns
or Moons having any thing to do with the Water ^ a bufinefle,
for the full underftanding of which I ftand in need of a little
longer time to confider thereof, which the novelty and difficulty
of it hath hitherto hindred me from doing : but I defpair not, but
that when I return in my folitude and filcnce to ruminate that
which remaineth in my fancy^ not very well digefted, I (ball
make it my own. We have now, from thefe four dayes pif-
courfe, great atteftations, in favour of the Copernican Syfteme,
amongft which thefe three taken : the firft, from the Stations and
Retrogradations of the Planets, and from their approaches, and
receffions from the Earth ; the fecond, from the Suns revolving
in it felf, and from what is obferved in its fpots s the third? from
the Ebbing and Flowing of the Sea do ftiew very rational and
concluding.

S A L V. To which alfo haply , in fliort , one might adde ^
fourth, and peradventure a fifth ; a fourth, I fay, taken frpr"
the fixed ftars, feeing that in them,upon exaS obfervations, thofe
iTiinute mutations appear, that Copernicus thought to have been
infenfible. There ftarts up, at this inftant, a fifth novelty, fro^
which one may argue mobility in the Terreftrial Globe, W
means of that which the moft Illuftrious Signore C^fare^oi the
noble Family of the Marfilii of Bologna , and a Lyncean M^'
demick, difcovereth with much ingenuity, who in a very learned
Traa of his, {heweth very particularly how that he had obferved
^^^JJ5^t^ual mutation, though very flow in the Meridian hi^f
of which Treatife, at length, with amazement , perufed by

Dialogue. iV. 415

I hope he will commuhicite Copies to all thofe that are Students
Natures Wonders.

S A G R. This is not the fir ft time that I have heard fpeak of
Ac exquifitc Learning of this Gentleman , and of his fhewing
himfelf a zealous Patron of all the Learned, arid if this, or iny
other of his Works fliall come to api^ear in puMique, we may be
rforehandaffurcd, that they will be received, as things of great
Value.

S A L V. Now becaufe it is time to put an end to cur Difcour-
fe, it remaineth, that I intreat you, that if, at more leafure go-
ing over the things again that hive been alledged you meet
with any doubts, or fcrupfles ndt wdYl refolved, you will excufc
overfight, as well for the noVclty of the Notion, as for the
^eakneffe of my wit, as alfo for the grandu're of the Subjear,
alfo finally, becaufe 1 do not, nor have pretended to that af-
fentfrom others, which I my feff do not give to this conceit,
which I could very eafily grant to be a Chym^ira^ and a ttiecr
paradox and you Sagredus, although in the Difcourfcs paft
y6a have many times, with great applaufe, declared, that you
Were pleafed with fomc of my conjreaures, yet do I believe, that
that vvas in part more occafioned by the novelty than by ^ the cer^
tainty of them, but much more by your courtcfie, which d?d
think and defire, by its affent, to procure me that cdntent Which
We naturally ufe to take in the approbation and applaufe 'bj? bur
own matters : andasydur civility Hith obliged me to yoa j fo
am 1 alfo pleafed with the ingenuity of Smflkim. Nay|^ his
conftancy in maintaining the Doftrine of his Mafter, with To
much ftrength & undauntedncfs5hath made me nluch to love him.
And as I am to give you thanks, SagiredTts, for yo'ur courteous at-
feftion^ fo o( Simplicinsy I ask pardon if I have fonietitne^J
m.ved him with my too bold and refolute fpeakihg : and let him
W afl-ured that I have not done the fame out of any inducement
offinifterafFcaion, but onely to giVebim occafion to fet before
Us more lofty fancies that might make me the more knowing. .

Simp There is no reafon why you fliould make all thefe e?^-
^rfes, that are needleffe, and efpecially to me , that being accu.
ftomedto be at Conferences and publique Difputes, have an
hundred times feen the Difputants riot onely to grow hot and an^
g^y atone another, but likewife to break forth into injurious
^ords, andfometimestocome very neer to blows As tor the
paft Difcourfcs, and particulatly in this laft, of the reafon of
Ebbing and Flowing of the Sea, I 4^^%^^ ^P^,^'^ ^^^^^h,
^^^y well apprehend the fame, but by that flight I^e^, what c-
ver it be, that I have formed thereof to my lelt , I conteffe that
your conceit feemcth to me far more ingenuous than any of ail

tnol€

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

G; G A L I L ^ u s ^ Sjfiewe.

thofe that lever heard befides, but yet ncvcrthelefle I eftecmit
not true and concluding ; but keeping aUvayes before the eye?
of my mind a folid Doftiine that I have lcarn*t from a moA
learned and ingenuous perfon, and with which it is neccffary to
fit down I know that both you being asked. Whether God, by
his infinite Power and Wifdome might confer upon the Element
of Water the reciprocal motion which we obferve in the fame in
any other way, than by making the containing Veffel to move : I
know, I fay, that you will anfwer, that he might, and knew hoW
to have done the fame many wayes, and thofe unimaginable to
our (hallow uoderftanding : upon which 1 forthwith conclude?
that this being granted, it would be an extravagant boldneffe
for any one to goe about to limit and confine the Divine
Power and Wifdome to fome one particular conjefture of
his own.

S A t V. This of yours is admirable, and truly Angelical Vo'
ftrine, to which very exaftly that other accords, in like manned
divine, which whilft it giveth us leave to difpute, touching the
conftitution of the World, addeth withall (perhaps to the end,
that the cxercife of the minds of men might neither be difcou-
raged, nor made bold) that we cannot find out the works made
by his hands. Let therefore the Difquifition permitted and or-
dained us by God, afllft us in the knowing, and fo much more
admiring his greatnefTc, by how much leffc we finde our felve^
too duU to penetrate the profound Abyffes of his infinite Wif*
dome.

S A G R. And this may fefvc for a final clofe of our four dayes
DifputationS) after which, if it feem good to Sahiatusy to take
fome time to reft himfelf, our curiofity muft, of neceflity, grant
him the fame, yet upon condition, that when it is leiTe incommo-
dious for him, he will return and fatisfic my defire in particular
concerning the -Problemes that remain to be difcuft, and that I
have fet down to be propounded at one or two other Conferen-
ces, according to our agreement : and above all, I fliall very
impatiently wait to hear the Elements of the new Science of our
Academic^ about the natural and violent local Motions. And
in the mean time, we may, according to our cuftome, fpend atJ
hour in taking the Air in the Gondola that waiteth for us.

F IN I S.

. BIBLIOTHECA
UNIVERSITATIS
BAUNIENSIS

THE

Ancient and Modern

DOCTRINE

O F

Holy Fathers,

AND

ludicious Divines,

CONCERNING

^he ralh citation of the 1 eftimony of Sacred

SCRIPTURE, in Conclufions mecrly Natural , and
that may be proved by Senfible Experiments, and
Neceffary Demonftrations.

Written, fomc years fince, to GratiBc The moft StaEN*
CHRISTINA LOTHARINGA, ^rcfe.
DutchefsofrVSCANTi

Galileo Galilei, A Gentleman of

Florence, and Chief Philofopher and Mathematician to
His moft Serene Highnefs the Grand D V K E.

And now rcndrcdinto tnglijh from tbt Italian,
B Y

Thomas Salusbury.

^'>turamKerHn,,n.venire,difciU,&Hbiin-vemrh^ indicat,
in -vulgusy nefas. Plato. ^^^^

LONDON,

Wedbv William LEtBOURN, i66<;

i Hljh

4i8 The Authority 0/ Scripture,

arc obfcure and hard to be underftood by the meer help of
ratiocination; where treating (as we) of a certain natural conclu-
Nurjc an Concerning Celefiial Bodies, he thus writes : (a) But notff

ttm!(ervMk fern- hu'vitig evcTtnore a refpM t(k th moderation of pious Gra'z/itjiy
ferntoderAtionepia oHght to bclie'ue nothing unad^ijecily in a donbtfiil foint\ '9*
ilalle^de lJ*\h- fve coucei'ue a prejudice againji tbat^in fa^vonr to otirErrotir^
fcttr a tenter e Ae- whichTruth hereafter may difco^tr to be no wife contrary to the

Sa^ed Book/ either of, be 0li«r^cn>Tefian.ent. .
fatcfecerity quam- It hath fince Come to pafs, thatTime hath by degrees dilco
VH Lthru^^KBi^, vered to every one the truths betore by me indicated: and to-
reterify five No- gcthcr With the truth ot the iao^, a dilcovery hath been made
vi^ntiiiotnodo ejfc the difference of humours bctwccu thofe who fimply and wit^^'
flwL '^pr7p^{r'a' oi^paiOon did refufe to admit fuch like Fh^nomena for true, and
moremmfiri err"' t^^(ijji^iio;to theif! inctcdulity had added fome difcompofed af'
'^'^Lib^f' Genefi feftion: For as thofe who were better grounded in the Science of
ad Literam in Aftronomy, and Natural P hilofophy^ became fatisfied upon tn)[
firft ntimationof thenews 5 fo all thole who ftood not in tli^
Negative, or in doubt for any other reafon , but becaufe it
an unlookt-for-Novelty,and becaufe they had not an occafion o^
feeing a fedfibbcj^periment thereof, did by degrees come to fa*
tisfie thfemfelves : But? thofcr who be fides the love they bore to
ihcn fii^ft^Errour , have I knownot what imlaginary intercfs
rend^'rfiem difaflfei^d vnot fo much towards the things , as to-
wards tfee Author of them, not being able any longer to d-i^X
them, cpnceal thcmfclves undor an obftinate filence j and hcit^S
exafperat^d more than ever by chs^t whereby thofe others W^f^
fiatisfied arid convinced, they drivert t^^ thoughts to other pf^'
lefts, and ieek to prejudice me fome other wayes : of whooi I
gi^cf$ that l would make no more account than I have done ot
thofe whc^ heretofore have contradided me (at whom -Iffalwaies
laugh, as being aflured of the ilTue that the bufinefs is to have)
kut that I fee that thofe new Calumnies and Perfecutions do not
demmine in our greater or leller Learning (in which 1 wiU fcarce
pretend to any thing) but extend fofar as to^tempt ta afpetlc
me witb Crimes which ought to be,and are m^ abhorred by
than Death it felf : Nor ou^ht I to content my felf that they
are known to be unjuft by thofe oncly who know me and theiO)
butby ^i men whatloever. They perfiftiiig therefore in their
firft Refoktion,Of ruining me aiid whatfoever is mine , by al*
imaginabie waiesi and knowing how that I in ray Studies o
Aftronomy and Philofophy hold , as to the Worlds Syft^tn^^
That the Sun, without changing place, is fitilate in the Centre
oftheCbnverfionof theCeleftialOrbesi and that ilie E^^^"j
convertible about its own Axis, moveth it felf about the Sun •
Andmoreovcrunderftandipgjthatl proceed to maintain ^'^j?^?^

/» Philosophical Controversies;

fition, notonel} by refuting the Rcafons of F^(?/<?wj^ and Arifio^
^^^5 but by producing many on the contrary , and in particular,
foiiic Phyfical pertaining to Natural EfFeds, the caufcs of which
perhaps can be by no other way afligncd ^ and others Aftrono-
wiical depending upon many circumftances and encounters of
«ew Difcoverics in Heaven, which manifeftly confute thePtolo-
n^aick Syfteme, and admirably agree with and confirm this other
Hypothcfis : and poffibly being afliamed to fee the knowa truth

other Pofitions by me alfcrted, diflferent from thofe that have
been commonly received j and therefore diftrulting their de-
fence to long as they fliould continue in the Field of Philofo-
phy : for thcfe refpefis, 1 fay, they have refolved to try whe-
ther they could make a Shield for the fallacies of their Argu-
inentsof the Mantle of a feigned Rcrligion, and of the Autho-
rity of the Sacred Scriptures, applyed by chem with little judg-
Daent to the confutation of fuch Rcaib.is of mine as they had
neither underftood, nor fo much as heard.

And firft, they haveindeavourcd, as much as in thcta liay?, ta
divulge an opinion thorqw the Univerfe, that thole Propofitions
•^re contrary to the Holy Letters, and confequently DaimiabJe
*nd Heretical : And thereupon per^^eivipg, thu for the laofi:
part, theinclination of Mans Nature is more prone to imbrace
thofe enterprizes, whereby his Neighbour may, although un-
j^tly, be opprefTed , than thofe fron;i whence he may receive
iiift incouragement , it was no hard matter to find thofe Goia-
Plices, who for fuch (that is, for Damnable and Heretical) did
from their Pulpits with unwonted confidence preach it, with but
an unmerciful and lefs con fiderate injury, not only to this Do-
^^j"e, and to its followers, but to all Mathematicks and Ma-
thenaaticians together. H<^*rcupon aiTuming greater confidence,
*nd vainly hoping that that Seed v\fhich firft took root in their un-
bound mindes, might fpread its branches, and afcend towards
Heaven, they went feathering rumouiiS up and down among the
People , That it would, ere long be condemned by Supreme Au-
thority : and knowing that inch a Cenfnr^ would fupplant
not onely thefe twoConclufions of'thc Worlds Syileme, buif
^ould make all other Aftronomical ^ind Phyfical Qbfervauons
that have correipoiKience and neceffary conncftion therewith to
l>ecome damnable, to facilitate the, bufinefs they feck all they
to make this opinion(at Icaft aniojigthe vulgar) to feem new,
peculiar to my felf^ not owning to know that mholas Cofer*
^HHs was its Authom, on ra(pr Heftorer and Confirmer : a per-
Jpn who was not only a Catholick, but a Prieft, Canomck, and
^ ^fteemed, that there being a Di£pute in the LiUeran Council^
Mer Lfp X. touching the corteaioa o£ the Eccleltaftick Ca-
lender

439

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

The Authority of S c a i p t u r e,

lendar, he was fcnt for to Rome from the rcmoteft parts of
Cerntanyy for to affift in this Reformation, which for that time
was left imperfea , onely becaufe as then the true mcaiure ol
the Year and Lunar Moneth was not exaftly known : whereupon
it was given him in charge by the Bifhop of Scntprunia 3 at that
time Supcr-intendent in that Affair, to learch with reiterated
ftudies and pains for greater light and certainty,tonching thoic
Coeleftial Motions. Upon which^with a Labour truly AtlanticK
and with his admirable Wit, fetting himfelf again to that Study,
he made fuch a progrefs in thefe Sciences, and reduced the
knowledge of the Coeleftial Motions to fuch cxaftncffe, that he
gained the title of an Excellent Afironomer, And, according
unto his Doftrinc, not only the Calendar hath been llnce regU'
lated, but the Tables of all the Motions of the Planets have al-
fo been calculated : and having reduced the laid Doftrine into
fix Books, hepubliflied them to the World at the inftancc of
the Cardinal of Cafna^ and of the Bifliop of Culma. And \^
regard that he had re-alTumed this fo laborious an enterprise by
the order of The Pope \ he dedicated his Book De Ke^uolntiorir
bus CoiUfiibus to His SuccefTour, namely F^«/ IIL which, being
then alfo Printed, hath been received by The Holy Church,
read and ftudied by all the World, without any the leaft
brage of fcruple that hath ever been conceived at his Doftrine?
The which, whilft it is now proved by manifcft Experiments aiiO
ncceflary Demonftrations to have been well grounded, th^^^
want not perfons that, though they never faw that fame Book 1^'
ter cept the reward of thofe many Labours to its Authour, h)'
causing him to be cenfured and pronounced an Heretick ^ an^l
this, only to fatisfie a particular difpleafure conceived, without
any caufe, againft another man, that hath no other intercft iti
Copernicjfs^ but only as he is an approver of his Doftrine. _

Now in regard of thefe falfe afperfions, which tney lo u^^).^"*;/
feek to throw upon me, I have thought it neceflary for n^y )^*"'
fication before the World f of whofe judgment in matters 0
Religion and Reputation I ought to make great efteem)
difcourfe concerning thofe Particulars, which thefe men product
tofcandalizeand fubvert this Opinion, and in a word, to con-
demn it, not only as falfe, but alfo as Heretical^ continually
making an Hipocritical Zeal for Religion their Shield j going^ ^'
bout moreover to intereft the Sacred Scriptures in the Difp"^^!
and to make them in a certain fenfi|Minifters of their deceipt*^
purpofes: and farthermore defiriiflpif I miftake not, contrary
the intention of them, and of the Holy Fathers to extend (that

not fay abufe)their Authority,fo as that even In Conclufions
mccrly Natural, and not de Fide, they would ha^ us altogeth<?r
^ ' leave

Jw Philosophical Controversies.

leave Senfe and Dcmonftrative Reafons, for fome place of Scri-
pture which fometimes under the apparent words may contain
a different fenfe. Now I hope to (hew with how much
greater Piety and Religious Zeal I proceed^than they do , in that
I propofe notjthat the Book of Copernicus is not to be condemn-
ed, but that it is not to be condemned , as they would have it 5
without underftanding it, hearing it, or fo much as feeing it ^
and efpecially he being an Author that never treateth of matters
of Religion or Faith , nor by Reafons any way depending on the
Authority of Sacred Scriptures whereupon he may have crroni-
oufly interpreted them^ but alwaies infifts upon Natural Conclu-
fions belonging to the Celeftial Motions, handled with Aftrono-
inical and Geometrical Demonftrations. Not that he had not a
refpefi to the places of the Sacred Leaves, but becaufe he knew
Very well that his faid Doftrine being demonftrated , it could
not contradift the Scriptures, rightly, and according to their true
leaning undci flood. And therefore in the end of his Epiftle
Dedicatory, fpeaking to The Pope, he faith thus : (^) // there
fioHld chance to be any Uat^ologifts, who though ignorant in all
fhe Mathematifks y y^t pretending a skill in thofe Learnings^
jhoHld dar^yUponthe authority of fome place iof Scripture wrejied
to their purpofe^ to condemn and cenfure this my Hypothefesy i
T/alue them not^ but fhall flight their inconfiderate Judgement For
it fs not unknown^ that Laftantius (otherwife a Famous Author^
though mean Mathematician^ writeth *very childijhly touching the
form of the Earth, when he fco^s at thofe who affirm the Earth to
be in Form of a Globe. So that it ought not to feem firange to the
^^genioHs ^ if any fuch fijould lih^wife now deride hs. The Ma-
ihematicl^s are written for Mathematitians^ to whom Qfldeceii/e
not my felf) thefe Labours of mine Jhali feem to add fomething,
^ alfo to the CommoU'Weale of the Churchy whofe Government is
»w in the hands of T our Holinefs.

And of this kinde do thefe appear to be who indcavour to
perfwade that Copernicus may be condemned before his Book is
^^ad i and to make the World believe that it is not onely lawful!
^^t commendable fo to do, produce certain Authorities of the
Scripture, ofDivines, and of Councils ^ which as they are by me
had in reverence, and held of Supream Authority ,infomuch that
J fliould efteem it high temerity for any one to contradift them
^hilft they are ufed according to the In ftitutesof Holy Church,
fo 1 believe that it is no errour to fpeak, fo long as one hath rea-
fon to fufpea that a perfon^iath a defire , for fome concern of
^»own, to produce and allcdge them,topurpofes different from
^^ofe that arc in the moft Sacred intention of The Holy Church.
Therefore I not onelv proteft (and my finccrity fhall manifeft it
^ ^ fdO

43^

{c)Siforufeeru»t

cum omnmm Ma-
thematicum igna-
ri fittt'i tamendeiit

mttnt, propter ali'
^Mtm locum Scri'
pturd^ma/c adfu^
urn profofitum^ dt-
tor turn , aufi fue-
rinthfe meumin'
flitutum reprehen*
dere ac inJcStdr/y
iUot nihil morory
ad(o utctiam illo-
rum jftdicittm^tan"
qtiAtn tcmrsrium
contemuAm. Norn
enim ohfcurtim ejt^
Ld^AHttum , eele-'
lebrem Alioqui
Scriptorem , fed
AlAthemAticum
fArvum^Admodum
pueriliter deformA
Terr A loqui , cnm
dertdet eos , <jfti
TerrAmfilohtfor'
mam hAhere prodi^
derunt, Itaquenon
debet mirnm vidf
ri fludtofisy fi qui
tAleSy Kos ettam ri-
debunt.MathemA-
ta MAthemAticit
fcribumur ; iiuibui
& hi noflrt Idbo^
res^ (fi mg nonfAl-
lit opinio ) vtde»
bunturetiAm Ret'
publtcA EccleftA*
fiicA coitdficere 4-
li(^md,cujHi PriM"
cipAtum T0A SAn-
tiitAS nnnc t€net»

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2°K.B. 9,163

The ^uthorhy 0/ Scripture,

fel£) that I intend to iubmit my felf freely to renounce thofe er^
rors, into which, through ignorance J may run in this Difcourf^
of matters pertaining to Religion , but I farther declare, that \
defire not in theie macteis to engage difpute with any on^, al-
though it fliould be in points that are difputable : forn[iyen4
endcth onely to this, That if in thcfe contidcrations , befides rry
own profeffion, amongft the errours that may be in them , thcpe
be any thing apt to give others an hint of fomc Notion beneficial
to the Holy Chqrchjtouching the determining about the Coper-
Syliemc, it may be taken and improved as {ball fcem beft
to my Sjpc riours : If not, let iriy Book be torn and burnt ^ f^r
that I do lie u her intend, nor pretend to gain to my lelfany frui^
from my Wiitiiigs, that i- not Hous and Catholick. And more^
over-, a]tjiOugh that many of the things that I obferve have beefl
ipoiien in.my own heani,g, yet I (liall freely admit and grant
thofe that ipatietlv m , that they never faid them , if fo they
p'eaic , hit co .l^is that 1 might have been miftaken : And
tiierciore Wiiai. I fay, let it be fuppofed to be ipoken not by themi
but by ihofc which were ot this opii»ion.

The modvc la^rcfore that they produce to condemn tbeOpi«
nion of the Mobiliry of the Earch^and Stability of the Sun, is?tbal
readin g in the Sacked Leaves, in many places, that the Sun
veui, that the Earth ftandeth ftilU and the Scripture not being
capa t 'lc of lying, or erring, it foUoweth upon neceffary conf<^'
quence, that ihe Pofiwionoi thofe is Erronious and Heretical,'^
mamtiin that the Sun of it lelf is immoveable , and the Eafth
moveable,

Touching thio Reafon I think it fit in the firft place , to com
fider, Thar it is bo(h pioufly fpoken,and prudently aflSrmed, Th^?
the Sacred Script ure can never lye, when ever its true meaning i^
undeillood : Which i believe none will deny to be many tim^j
very abftruce, and very dilfereut from that which the bare found
of the words fignificth. W hence it cometh to pafs, that if ^^^^
any one Ihould conftantly confine himfelf to the naked Gram?
matical Sence,h^ might > erring himfelf, make not only Contra*
didioiiSand P opofuions remote from Truth to appear in the
Scriptures, but alfo grofs Hcrelies and Blafphemies : For that
fliould be forced to aifign to God feet, and hands, and eyes, y^^
more corporal and humane afFcfiions, as of Anger , of Repc^^"^
tance , of Hatred, nay,2^nd fometimes the Forgetting of thing?
paft,and Ignorance of thofe to come : Which Propofition^, li''^
as (lo the Holy Ghpft affirmeih) th^ were in that manner P^^'
nounced by the Sacred Scriptures, that they might be tlcco^^^'
dated tp the Capacity of the Vulgar,who are very rude and
learned (i, Ukewife, for the fakes of thofe that deferve to be di;

In Ph iLOs oPH I CAL Controversies.

^msuifhcd f fdm the Vnfgar, it rteteffary thaff ^gwve aDd^bilful
Expofitofs produce tHetyuefcrfesof.^to^
WlarRetifoVwhythc^a^ediaite^otKler fo^^
And this'u it)oarhie fo wae add common an!ongtt-aviii«v
tfiit it Svddld^be fiJterflUoui ie- prodwccany acteftatioji

'"HeilCe rethinks 1 ma.^with miwh irtore rcafba oonckide, that .
*fi fairie*h5lVWtir,'wte« ever it hath Had occafion tb pronounce
^natural Conclafibtt;and ^'F"*"/

"•ore abftrucc, and difficult to be underftood , hath not failed to
^Vetvetfti5 Rule, that fo^k might not caute confufion'. tni.thc
"llWsof thbfc vcry^rople, and reiider tbeitt the more-toDtu.
nticidus agrinft the Do&ines th«v«ere more luWimely myften-
ofis For THke as wc havefaid, and A^s it plainly appeareth):oUt
^'f-'the fol'e^cfpea of condefcending t6.Pof.ulaf CapaORy, the
So-ipture hith not fcrupled to ffiadov* over moft principal and
fundamental Truths, Attributing, even td God h.mfelf,.<5ualiti«
e^^treatnly rtinote frwni and contrary unto his Effence. _ Who
'vould pofitively affirm that the Sdiiptur? , laying fde thzx re-

ftlf with all' tigour, withtnthe bareafnd narrow literal fcnfe of
ttife words >- T^nd efpedally , irt mentioning of thofe Crcai
totes, things not at alFcdncerning the primary Inftitut^n of
t&c faWc Sacred VoloiAe, to wit, tlie Service of God and the
filvation of Souls, and in things infinitely bfeyond the ajppre.

^C)^^cin:6f itieVulgar>;- " . , . r.-r 'a''
this thereforcbcirig^rantedvmethinksthat in the Diftuffion

of Natural -Problemes,we ought iibt to begin: at the authonty
tO^lacesofWurevbuta.^^^

g^y Ccmonftratio^, ^ for. fr^^^ the firft,

oacred Scripture and Nature um i nM>r.

««e Executrix of GodVcommai,* : ■ And nrareovK it being

«'ng Natural EfFefts which eitheir Senfiblc Experience tets be-
^^'^t notj^pon any aiii>antrto^>^^«lled into qucftion, mj**

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2°K.B. 9,163

434

Not definimui ,

tnra co^mfceH'

Urind reeogmfcen-
dttm' NdtuTAex
eptrt^m; Dn^ri-
md ex fi adtcatio-
nihtu,

Tcrtul. adi» cr.
Marc ion. lit*, i.
cap. 18.

The ^ utbority 0/ S c r i p j, u a :

lefs condemned upon the teftimony of Texts of Scripture, vvhich
may, under their wprdo, coiich Senfes fecmingly contrary there"
to j. In regard that every Exprcflion of Scripture is rjqt tied to
fo ftria conditipns, as every Effcft of Nature : Nor doth God
lefs admirably difcover himlclt unto us in Nature's Aflions, than
in the Scriptures Sacred Diflions. Which peradvcnturc ierttil-
//j/i intended to exprefb in thofc words ; (c) Weconclnde'i Cod
kk^ovons firjiy by hature and then a<^f/n . more farticuU^b.
known by DoBrim /. by Nature^ in hk Workj j by Do^rincy in
Word f reached. . " ,

But 1 will not hence affirm, but that we ought to have an e?^'
traordinary cftcem for the Places of Sacred Scripture, nay, being
come to a certainty in any Natural Conclulions, we ough^
to make ufe of ihcm, as moft ;ippofite helps to the true Exp^'
fition of the iavne Scriptures , and to the invcftigation of tb^^*^
Senfes which are neceffarily conteined in them, as moft true, afl^
concordant wich the Truths demoiiftiated.

This maketh me to fuppofe, that the Authority of the Sacr^^
Volumes was intended principally to perfwade men to the be-
lief of thofe Arcicles and Propolitions, which, by teafon they
fUrpafs all humane difcourfe, could not by any other Science? of
by any other means be made credible, than by the Mouth o^
the Holy Spirit it felf. Befides that, even in thofe Propofitioi^^>
which are not de Fide^ the Authority of the fame Sacred L<^^^^
ought to be preferred to the Authority of all Humane Science^
that pre not written in a Demonftrative Method, but either wit^
bare Narrations, or elfe with probable Reafons j and this I hol^^
to be fo far convenient and necelTary, by how far the faid V^'
vine Wifdome furpa{rcth all humane Judgment and Conjeflure-
But that that felf lame God who hath indued us with Senfes,
Difcourfe^ and Undcrftanding hath intejided, laying ^^^^
ufe of thefejio give the knowledg of thofe things by other nieansj
which we may attain by thefe, fo as that even in thofe Natural
Conclufions, which either by Senfible Experiments or Necelfaty
Demonftrations are fet before our eyes, or our Undcrftanding, ^'^^
ought to deny Senfe and Reafon, I do not conceive that I
bound to believe it , and efpecially in thofe Sciences, of whi^"
but a fmall part , and that divided into Conclufions is to h^
found in the Scripture : Such as, for inftancc, is thar of Afi^^'
nomy^ oi which there is fo fmall a part in Holy Writ, that it dot**
not io much as name any of the Planets, except the Sun and the
Moon, and once or twice onely Venm under the name of

For if the Holy Writers had had any intention to perfwad^
people to believe the Difpofitions and Motions of the Cceleft^^*
Bodies i and that confcquejitly we arc ftill to derive that 1^^^'

//^ Ph ILOSOPIC A L CoNTaOVERSl FS. 43<^

ltdge from the Sicrcd Books they would not, in my opinion, have
Spoken To little thereof, that it is as much as nothing, in compa-
^ifon of the infinite admirable Conclufions, which in that Sci-
ence are comprized and demonftratcd Nay, that the Authouvs
of the Holy Volumes did not only not pretend lo teach us the
Conftitutions and Motions of the Heavens and Stars, their Fi-
gures, Magnitudes, and Diftances, but that intentionally (al-
l^^ic that all thefe things were very well known unto them) they
forbore to fpcak of them,is the opinion of the MoftHoly & Mdft /JZ/^S^^^^^
Learned Fathcrs:and in S ./^w^«y?/^e we read the following words, j^^^r-* c<tit cre-
(^) h ts hk^wife lommonly ask^ed^ of what Form and Figure "j^^^^^ ^scnftZZ
inay believe Heazfen to he^ according to the Scriptures : For noftrM: MhIU e-
^^ny contend much about thofe matters^ which the areaterpru- ^^f'
^^nce of our Auihorsioath forborn to Ipeal^of^ as notVingfurther
^^gthetr Learners in relation to a blejfed life j and^ ^^^^^^ ^ tllT^fltf^'Td

chiefefi thing) taking up much of that ttntc which fhould be '^hIt7mZ*iilm
fpent in holy exercifes. For what is it to me whether HeA'ven^ as profttturof difcen-
' Sphere, doth on all fides environ the Earth, a Mafs ballancedin t'^^fZ/^Z^^fly
^he middle of the IVorld-iOr whether lil{e a Dijh it doth onely co<ver mtthum pr^Uxay

overcad the fame ? But becanfe belief of Scripture is urged for f '''^'^
^bdt caufe^which we hai/e oft mentioned^that ps,lhat none through tcmporHm fpMtiM,
knorance of Di'vine Phrafesiwhen they (hall find any thin^ of this ^"''^ ^"'"^ "'^'^^

1 ] • I / n it 1-1 r pertinct , MtrHm

future m,or hear any thing ctted out of our Dimes which may jeem Calttm^ficMtSpha*
'o oppofe manifejl Conclufions , fhould be induced to fnfpeSl their ra^^^dique cencln-
^^Hthjwhen they admonifJ^^relatCy^ deliver more profitable matters f^ldUMnZirt!^-
briefly be it f pollen, touching the Figure of Heu'venythat our Au- ir i'l>rAum ; an
^hors knew the truth: But the H. Spirit would not, that fHen fhould \^^Zf^^^*_^ ^Xc-
^^f^^n-what is prof table \o none for falvation. Int difau ^ ope-

? ^^j^ ^^^^ 4(rf -wr Script KrjtrHnty propter illam caufa»t,<jfiam moh femel commemorAvimw^ Ne fctlitet
^**ifeji44m eioijHia dtvina ttsn tnlelltgens^cum his lebm tale r< li<jHtd-ve I invenerit in Lihrif iV^/rftr, t/f/ ex Hits
**idiveYit^ ^^^^ t:gy.ceptu a^'erti^mhs adverfan videdtur^ rulto modo eis^ cetera milia monentihits^ vel nMrr^ntihtUy
VhraHM»ttantthw, credit : Brevner dtfct^dy^m efi, de Jigura C^Hyhcc/cfp Antores noflros, tjUod verttas ha-
I*' SedSpiritumT)et.qutpcrnfosloquehnfir, nolHijfe ifla docere homines, mlb ad falntem profmura.D.
^^'guft. Li5.2.l)?Gcn.ad htcramiCap. g.hk^n etiam Icguur apud Petrum LomhardHm Magirtruni Jemcntisnim.

And the fame intentional filence of thefe facred Penmen in
^^termining what is to be believed of thefe accidents of the Ce-
'^ftial Bodies, h again Itnted to us by the fame Father in the en-
^"^^g 1 o. Chapter upon the Queftion, Whether we are to believe
' ^'^ai Heaven movcth , or ftandeth lHll,in thefe words :{d) There ( d) ^e Mom
^'^fomeofthe Brethren that ji art a que ft ion con certiing the motion 'l^]"^^^^^^^^^
^fHea^ven Whether it be fixed^ or moved : For if it be moved fih/Kmrnovent^M-
[f^y they] how is It a Firmament > If ttftandfttll, how do thefe tr^^/r/^.
^^^rs which are held to be fixed go round from Eaft to W eft , the vetur, in^tii^'^ty
"^''^ Northern performingjhorter Circuits near the Fole ^ fo that V^;^^ J'^^J
^ea<ocn, if there be another Fole, to us unknown, may feem to re- autem fiAt^n^^m^-
'^ohe upon fame other Axis \ but if there he not another fole, tt crZuZ
thought t0 move as a D if ens } To whom I reply , that tm, ab Orieme ,»

I i i 3 thefe Ocadtntem drcM*

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2°K.B. 9,163

The Authority 0/ S c r i p t u r e,

o»»( , SePteMrh- thefe points require many fubtii and frofomd Keafonf, for the
;;'l7Jr«2 maki«gOHt whether they be really fo, or no; the undertaketng and
mm p,r»gtnuh«, ; difeHffing ofwhtcb is neither conjijient with my leaf ure, nor their
;,«::r«f/.:: d,uy, ^^hon^Idefretotnftmamthe neceffary ntatter.mredt-
cardo^exatiover- reBl) conducing to their falifation ^ and to the bene^tof Ih^

fia-Mrm nnllsisA- , , • U.r^ife^

i,H6 cardotfl , vci From which (that we may come nearer to our particular caiy
XLa^ll OutZ i^^c^ffii^Iy followeth, that the Holy Ghoft not having intend-

whether Heaven mo veth or ftandethftilh i^^^
fuhiitbm & ub9' whether its Figure be in Form of a Sphere^or of a Difcus , or di-
Tfl^percj::!^- inPUnHmi Nor whether the Earth be contained in the
re frciputlr ^ Centre of it, or on one fide-, he hath much lefs had an intention

and in fnch

^nJu atque tra- a mauncr, cgnnefied to thefe already named , that without ibc

^ ^^^^ ^^^^ ^^^^^

{l^'fff^Thlt,qlZ part h which are.'The determining of the Motion and Reft of th^

fs^alaT/cclc7J ^^^^ "^"^ ^^^^^ ^^^^ ^P^"'^

mceffJ^utiiitlu purpofely pretermitted to teach us ihofe Propofitions,as nothing

cf^imm informa- concerning his intention, that is, our falvation , how can it be af-
firmed, that the holding of one part rather than the other, ft^"^^
befoneceflary^asthat it is de Fide, and the other erronious •
Can an Opinion be Heretical , and yet nothing concerning
falvation of fouls > Or can it be faid that the Holy Ghoft purp^'

^Card.Baronius. fed not toteach US a thing that concerned our falvation ? 1 migj
spirttui f4.ns l^ere infert tfte Opinion of an Eccjefiaftical * Perfon, raifed to tn^

mememfuif'.ms degree o£ Engine ntiffimoyto vfit^ That the intention of the$ti^v

docerc^qnomoAoad Q^^^a ^ ^-^ teach m how We fhall go to Heaven^andnot how H^^"

C ilium edtur ino» J ^ J <^

Autemy qttomodo *ven goeth,

i^^ium ffradtatur. But let US rctum to cottfider how much ncceflfary Demonftf^j
a.d.nai.3ar. ^j^j^^^^^j ^^^^^[^1^ Experiments ought to bieefteemed in Natural
Conclufionsjand of what Authority Holy and Learned Divjnes
have accounted them,from whom amongft an hundred other atte-
JiJ^':::Z ftation3;^fe have thefe that follow:(0 We mnU alfo carefullj^
dum, & emnino beedi^d altogether awid in handling, the DoSrine (?/ Moles,
tKZt:!'^:: ^^^^^^^^^ a^rmatt^elj^and .confdentl^^^^^^^

C-isD^nrina,qu,c- contraMieth the manifefi Experiments andReafons <^f i^l^^^L
q»am afrm^te & ^f^^^ ^^^^^ Sciences, For fince allTruth is agreeable to TrHtP^
ZTp^'TIZ'. the Truth of Holy Writ cannot be contrary to the foltd ^eafi^
<7«.^rrp«^.^^^^ Experiments of Humane Learning.

net mantfeftistex^ r J n /< umVcf^

periTKertis & r^thmfuf PhthfophU.vel aliarum DtfciplhArum. N^mf*e cum Verum omne femper ^'^^^^
congruat.nonpotejtye.itMS^crarHmLitteranm, Iberia Rationtbw & Experiment ts Hurnan^rum
rttm ej[e contrarU^ ^zxtt, in Gzn, circa Principijm

(/; Si «^'«'f'- And in St. Angufiine we read.: {f) If any one

fi/i certdqfff ii'*^^' » - - ^ ' . . /i 1 1

OHiy veldt
rum Litter arum
ohjicitnr amort'

fanaa- the Authority of Sacred Writ.againfi dear and mantfejl ^^V^^]
terarum he that d<ah fo^k^Qws not what he undertakes : For he ^ ^

]

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2°K.B. 9,163

In Philosophical Controversies:

7li the rrHth,not the fenfe of *he Scripture^ Cri>bkh k ie-

43-7

againlithe JrHth,tiot the Jenje oj^u^ - - -• ^i,.^„it>c f^a, •

md his comprchenfion) hut rather hk own; not what ts Uttt.bHt ^ s„ip,uU

mjat.pncttn.' it in himletj , he fancyedto be iri it.

Tlis granted, and J being true, (as hath been fa,d) that two
Truths cannot be contrary to each other, « is the oSkc^J\
Judicious Expofitor to ftudy to finde the true Senfes of S^red
Texts, which undoubtedly ^hall accord with thote^Natdra Con-
clufie^s, of which manifcft Senle and Neceflary Denabnfu-atians
had before made tts fare and certain. Yea, ^^.^'ft^T^
Scriptures (as hath been faid; for the Reafons dledged, adm.rij
many places Expbfitions far from the Senfeof ^^^^f^J^^
moreover, we Lt bemg able tp affirm, that a" Ii> erpie«rs
fpeak by Divine Infpiration •, For (it jt were fo) thenahere
would hi no difFerenc'e between them abou, the Senfe.-f the
fameplaces; Ifhould think that it would be an aa of great pm
dence to make it unlawful for any one to ufurp Texts of Sa -
Pture and as it were to force them to maintain this or that Natuj

rS^RXn! may onetime or other affure us
ccuaiy . ^bounds to Wits of men ? Who wlH

r^ly d^cove ed and known ? Will not th^ th.t m oAe.pO.g
d ?alrcc with us, confefs this (and it is a great "at^)^"^^^

TruL which we know, are very few m ^^J^^
which we know not > Nay more, if we have « from jhe^^^,
of the Holy Ghoft, that Dem traduht Mmdnm diff^tmmt
.eorum, nt non tHveniat homo opm, quod operate efi Uem al>

n.u»e ; nor ought any potions .o be ifpkaM .f °°
hold in natural Difputes to that opinion which M P'"'""

th/^S'^nTeVially^touchrngProl^^^^^^^^^^
of y«rs,been controverted atnongft the g;";^J";""° ^

the Stability of the Sun -^^''^'If .f.^^f S^.^/^rf-
held by rvtb'"'oras, and by his whole Sed , by „
^cusZloltof thefameopininion V by/^y^'-^; f
of f C and by Flato himlelf, as ^r,^//. relateth, and of
Hieh P „ "ri writethin the life of N--, that the faid F a o
^vhen he was grown old, faid, It is a moft f '^^^^
otherw'fe The fame was believed by as
V^e haveit in ^rc/W^x ; and probably by Archmedes hm-

penetrare non po*
tutt) fedfuumpo'
tins ohjTcifverita-
ti: necidcjuod in
tAy (ed cfuod in fe-
ipf(f velHt pro ed
tHvenit^ opponit,
Epirt. 7. ad Mar-
ccllinum.

The Authority e)/ Scripture,

felfi» by Nim^ the Philofophcr, upon the teftimony of ^W^^'"^?
and by many others. And this opinion hath, finally, been am-
plified, and with many Obfervations and Dcmonftrations con-
firmed by yUchoUm Copernicus. And Seneca^ a moft eminent
Philofopher , in his Book De Cometis^ advertizeth us that \ve
ought, with great diligence, feek for an afllired knowledge,
whether it be Heaven, or the Earth, in which the Diurnal Con-
verfion refides.

And for this caufe, it would probably be prudent and profi-
table counfel, if befides the Articles which concern our Salvati-
on, and the eftablifhment of our Faith (againft the (lability of
which there is no fear that any valid and folid Dodrinc can fi-
ver rile up) men would not aggregate and heap up more, with"
out neceflity : And if it be fo, it would certainly be a prepoftc-
rous thing to introduce fuch Articles at the requcft of perfons
who, befides that we know not that they fpeak by infpiration
of Divine Grace, we plainly fee that there might be wiflied in
them the under/landing which would be neceffary firft to enable
them to comprehend, and then to difcufs the Demonftrations
wherewith the fubtiler Sciences proceed in confirming (nch
Conclufions. Nay, more 1 fliould fay, (were it lawful to ff^^^
my judgment freely on this Argument) that it would haply
more fu it with the Decorum, and Majefty of.thofe Sacred Vo-
lumes, if care were taken that every (hallow and vulgar VVritec
might not authorize his Books (which are not feldome ground^^
upan foolilh fancies) by infcrting into them Places of Holy Scri-
pture, interpreted, or rather diftorted to Senfes as remote from
the right meaning of the laid Scripture, as. they are neer to deri-
rifion, y/ho not without oftentation flourifli out their Writings
therewith. Examples of fuch like abufes there might many be
produced, but ior this time I will confine my felf to two, not
n>uch befides thefe matters of Afi}[onomy : One of which, is that
of thofe Pamphlets which Were publiflied againft the Mediceaf^
Planets, of which I had the fortune to make the difcovery h ^'
gaihft the exiftencc of which there were brought many places ot
Sacred Scripture : Now,- that all the World feeth them to be
Planets , 1 would gladly hear with what jiew interpretations
thofe very Antagonifts do expound the Scriprure,and excufe th^ic
own fimplicity. The other example is of him who but very
latejy hath Printed againft y4/?r(;«£/>//<:rx and FhilofopherSy that
the lyioon doth not receive its light from the Sun, but is of its ovv^
>^ature rcfplcndent : which imagination he in the clofe confi^^'
^*h, or,^ to fay better, perfwadeth himfelf that he confirmeth by
luiidry Xexts of Scripture, which he thinks cannot be reconciled
unleffc his opinion (hould be true and neceffiry. NevertbeJefl^J

/» Ph iLOsoPHicAL Controversies. 439

the Moon of it felf is Tenebrofe, and yet it is no leffc lucid than
the Splendor of the Sun.

Hence it is manifeft, that thefc kinde of Authors,in regard they
did not dive into the true Sence of the Scripturcs,would (in cafe
their authority were of any great moment) haveimpofed a nccel-
fity upon others to believe fuchConclufions for ""^^^
Pugnant to manifeft Reafon, and to Senfe. Which abufe Deus
"•vertat, that it do not gain Countenance and Authority ; for if it
ftould it wouldinafliorttime benecelfarytoprolcribe and in-
hibit all the Contemplative Sciences. For being that by iwture
the number of fuch 35 are very unapt to undeiftand perfedly
l>oth the Sacred Scriptures, and the other Sciences is much great-
er than that of Che skilfHll and intelligent ; thofe. of the firft fort
fuperficially running over the Scripcures,would arrogate to ihem-
felvesan Authority of decreeing upon all the Queftions in Na-
ture, by vcrtue of iome Word by them mifunderftood , and pro-
duced by the Sacred Pen-men to another purpofe J Nor would
the fmall number of the Intelligent be able toreprcfs the furious
Torrent of thofe men, who would finde fo many the more fol-
lowers, in that the gaining the reputation of Wile T T
Pains or Study, is far more grateful to humane Nature, than the
confuming our felves with reftlefs contemplations about the moft
painful! Arts. Therefore we ought to return infinite thanks to
Mmighty God, who of his Goodnefs freeth us from this fear, in
that he depriveth fuch kinde of pcrfons of all Authority and, re-
pofeththeConfulting, Refolving, and Decreeing upon, fo im-
portant Determinations in the extraordinary Wifdom and Can-
dor of moft Sacred Fathers i and in the Supream Authority ot
thole, who being guided by his' Holy Spirit, cannot but determin
HoHly : So ordering things, that of the levity of thofe other men,
{here is no account made.^ This kinde of men are thofe as I be-
Ji^ve, againft whom, not without Realon, Grave, and Holy Wri-
ters do fo much inveigh ; and of whom m particular S. H ^
^titeth • (e^this rScilicet the Sacred Scripture ) the talking uc»s»cTAmscn.
"Id r^onian^eLing old mn„, the talk.ati.e Sofhtfier M venture C^^.^i^X^
**Po»Jacerate, teach, and that before they ha-je learnt ,t. uwers j-,,,^ ^,,^^^
'W-e. l>%idej,^^g ,nto Ld.ords , P^^ff^/^^^/f & J^^-
^omtn :,oHchi«£ the Holy Scriptures. Others \0h ihame. f.,.u.,.uiZm.
^"^ ) Learn of Women what they tedch to Men ; and , as // tlJK j,„« ,„,^^
^'reLCZ/n a certain fac,Utyofn>ords,l >^^yf''yf^'"'fi; S^V-^^.fiZ;
i'"^^, expound to others rphat they nnderfiand not the fehcs I ,
^-^e.. tlfpeakof thofe of.y own Profefon who , ,f after H«

LeJL<r,L chance to attain to the Holy Ss^ptHres and tH,.U
'ilH^^hj:hftl peoplew,thafeSiedandSt.d.de.preffions ^g^S'A*
*hey affirtn that all they fay, is t$ be cntcrtamtA as the Law ofGodi^ i ifamink,

^ ^ ^ and fftod vires dfftenf,

449

^ ne rarutn hoC
fjt^ ejmiUm fact-
Ittdte verhruWj
im9 audAcia^edif-
feruNt alits^ tj!^oeL
ipji mn intelU"
gftnt, Taceo de
met jlmiltbtu , <^Pii
fi forte ad Scriptu-
fasSaft^a4, poft-
fecnlares Utterat
veverim , fef
mo*ie ccmpo/itOf
awem popatt mul-
fertnt ; qrucef tid
dixertnt , hoc Ic
gem Dei ppitaft :
Tiec fcire dignAn-
tur, ^Hidprophe-
^Hidt^pofioU
fenferint , fed ad
fenfttm fuum , <»-
congYH,^ aptant te'
pimo'ma : Sj:^*fi
grands (It ^& non
vitiociJfimHm do-
cendi genus , dt'
pravare fententf
asy & ad volun-
tatemfnam Sen-
fturamtrahere re-
pugnamem. Je-
ron. EpitL ad

P4«/, I03»,

The ^Htbcrify of S c r i pit u re,

and not ficofing to learn what th Prophti and Appfiles held,
they force incongrnom teflimonies to their ^ own Senfe. : As if ^
were the genniney dnd nt)t corrtlpt woiy efte^hing to defra'^e Sen-
tences^ and fVreJi the Serif tut t»£C or ding m/Mr flW/f fi^gm^
contradi^ory humour. : n -ilo t; . ■ 7 i

I will not rank among thefe Ikme fecular, Writers any i'^^^'
logifls^ whom I repute to be men of profou^d Learning, and iQ]
ber Manners, and therefore hold them in great #eem and vene-
ration? Xtt I cannot deny but that I h^yfc a certain, fcmple m
my iti^nd,andconfequently am dciirdu^ ffo have it« removed^
whilft I heaf chat they pretend to a power,pf conftraining others
by Authofity of the Scriptures to follow that opinion in NatiVl
ral Dirpu cations, which they think moft ag^ceth vvith the Tepct^
of that^:- Holding withal), that they are f^ot bound tO; anfw.e^,
theReifon^ And Experiments on the contrary : In .pxplicati^>i»
and (Jonfii^matiion of which their judgement they fay, That T/?^i
^%f^bdltTg the Qiiecn of all the Scknccs, fee ought not upon
atiy'^l^icMii^ttoftoopto accomodate herself to the Pofitions P*
thereft^'fefs worthy^ and inferior to her : But that^they ougW
to r^fer themfelvei^ tosher (as to their Sitpream Emperefs)
change^tttKl altet their Conclufions , aGwding^ti^,3>^^^^^M
Statu fdi'^ftd Decreets- : And t Hey : further add^ that ^^^j
inferior Science there fhould be any Conclufion certain by ve J
tue of Oettionftratiolid or experiments, to which there is fouP,^
in Scripture another Concluiion repugnant^ the very^ Profciior
of that Science ought of themfelves to refolve their Dcmonftratl-
ons, arid difcover the falacies of their own Experiments, without
repairlng tbtheologersandXextuaries, it not fuiting (as hatb
been faid) with the dignity oi theologie to ftoop to the inveftig^^'
tionof the falacies of the inferior Sciences ; But it fufficeth hej,
to determine the truth of the Conclufion with her abfolute A
thotity^, kndby her infallibility. And then the Natural Conei-
fion^ iii which they fay that we ought to bide by the meet A '
thority of the Scripture, without glofling , or expounding it ^
i'enfes different from the Words, they affirm to be Thole
vvhich the Scripture fpeaketh alwaies in the fame manner j an^
the Holy Fathers all receive, and expound to the Uu^

Senfe. ,1 r ^r^nCi'

Now as to thefe Determinations , I have had occafion to cony
der fomepiirticulars (which 1 will purpofc) for that I was maP
cautious thereof, by thofe whounderftand more than I in t^^ -
bufincffes, and to whofe judgements 1 alwaics fubmit , J
And firft I could fay, that there might poffibly a certain kina
equivocation interpofe, in that they do not diftinguifli ^'jf Pj J^ji,
minenccs whereby Sacred Theviogie meriteth the Title otCL

//2 Philosophical Controversies.

For it might be called fo, either becaufe that that which is taught
^>y all the other Scienccs,is found to be comprized and demonftra-
^ed in it,biit with more excellent means, and with more iiiblime
Lcarning^in like manner, as for examplejThc Rules of meafuring
of Land,& of Accountantlhip are much more excellently contain-
ed in the Arithmatick and Geometry of Euclid^th^n in the Prafti-
fcs of SuTveyours and Accomptants:Or becaufe the SubjeS about
which7/;e(7^5/eisconverfant,excellcth in Dignity all the other
Subjcfis, that are the Matters of other Sciences : As alfo becaufe
Documents are divulged by nobler waies. That the Title
^nd Authority of Queen bclongeth to Thcologie in the firft
Senfe, I think that no Thcologers will affirm , that have but any
^n. fight into the oth-r Sciences; of which there are none fas I be-
'ieve) that will fay that Geometry, Aftronomy Mufick, and Me-
dicine are much more excellently and exaftly contained in the
Sacred Volumes, than in the Books of Archimedes^ in Ptolomy, in
^(^etiHSy2ind in Caien. Therefore it is probable that the Regal
freheminenceis given her upon the fecond account, namely, By
J'e^fon of the Subjea, and the admirable communicatmg of the
Divine Revelations in thofe Coiiclufions which by other means
could not be conceived by men, and which chiefly concern the
acquift of eternal Beatitude. -Now i( Theologie hemg conver-
fant about the lofticft Divine Coritcmplatlbn, arid refiding for
Dianity in the Regal Throne of the Sciences, (whereby (he be-
Cometh of higheft Authority) defcendeth not to the more mean
and humble Speculations ot the inferior Sciences : Nay, (as hath
been declared above) hath no regard to ihem, as not concerning
Beatitude the ProfcfTors thereof ought not to arrogate to them-
felves the \fithority to determin of Controverficsin thofe Pro-
feffions which have becA neither praaifed nor ftudied by them.
Fo.thiswouldbeasifanAbfolute P/i"/^
might freely command, and caufe himfelf to be obeyed fliould
(being neither PhilJrian nor Arehitea) undertake to admtnifter
Medicines,anderea Buildings after his own faihion, to thegreac
endangering af the lives of the poor Patients, and to the manitelt
d^ftruaion of the Edifices. r Aa th^^

Again CO command the very Profcflbrs of ^^.--^ ^^^^^^
thcylf .hemfdvc. Ice to the confatmg of the.r own Obfe.va
tions and Demonft rations, as thoie that can be no o the, but
Falacies and Sophifmes, is to gnjoyn a thing beyond a poffib.-
lity of doina : For it is not oncly to command them that they do
4 fee .rhltM they fee, and that they do -otM.nd
'l-at which they underftand ; but that infecbng, they finde the
contrary of that whicli they happen to meet mth. Therefore be-
fore that tMs is to be done, It would bencceffary that they were

K k k ftewred

441

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2°K.B. 9,163

442

(g) Hoeiftdtt-
bitanter tenendum
ejt , m qHic<jmd
Sdpientes h ujtts
Mundi^ de Natti'
rm rerum veraci-
ter demonfirare
■potuerint^ ofi'enda-

non effe contran-
um : qi*iC£ju'd aw
tern tlliytn fuu vo-
lumtntbKS^ contra-
rium Smctm Lit-
teris decent , fxe
ulla dubiiatioue
creddmfu^idfa//f
fimum effe,^ (jAo-
cfHt modo pojfft-
mtUy etiam ojien-
damtu ; at^ue it a
teneamw Fidem
Dsmininofirt , in
ijMa [mnt abfcovdttt
emotes thefaurt
SaP'entiay ut ne-
ejue fa/fa Philofo-
Icqaacitate
fedMCamnryrxqi^e
fimuUta Rel'^*o'
nii fnperjiittone

ttrreamur^
Gen.adLitteram.

The (Authority 0/ Scripture,

/hewed the way how to make the Powers of the Soul to command
ione another, and the inferior the Superior , fo that the imaginati-
on and will might, and (hould believe contrary to what the Intel-
left underftands : I ftill mean in Propoiitions purely Natural^and
which are not fiffif'i^e, and not in the Supernatural , which arc
de Fide,

I would entreat thefe Wife and Prudent Fathers , that they
would withal diligence confider the difference that is between
Opinablc and Demonftrativc Do&rines : To the end, that

well

Weighing in their minds with what force NeceiTary Illations ob-
lige , they might the better afcertain themfclvcs, that it is not in
the Power of the ProfcfTorsof Demonftrative Sciences to change
their Opinions at pleafure 5 and apply themlelves one while to
on^ fide, and another while to another , and that there is a great
difference between commanding a Methametitian or a Philofo-
pher, and thedifpofing of a Lawyer or a Merchant i and that the
dempnffrated Concluiions touching the things of Nature and of
the Heavens cannot be changed with the fame facility, as the
Opit^ions are touching what is lawful or not in a Contraft , Bar-
gain, or Bill of Excliange. TThis difference was well underftood
by the Le:arned and Holy Fathers, as their having been at great
pains to confute many Arguments, or to fay better, many P^i-
lofophical FallacieSjdoth prove unto us 3 and as may exprefly
read in fome of them, and particularly we have in S. Jugufii^^
the following words : ( This is to be held for 4n nndonbt'
edTruthytloat we may be confide nty that what ei^er the Sages of
this World h^'z/e demonflrated touching Natural Foints^is no%^^^^
sontraiy to our Biples : And in cafe they teach any thing in theif
^ook^ that is c,ontrary to the Holy Scriptures^ we may without any
fcruph conclude it to be moflfalfe j And aceording to our ability
Ut us waks the fame appear: And let us fo k^ep the Faith of our
Lc^Xifp whom ar(i hidden all the Treafnres of Wifdom j that
he neither f educed with the Loquacity of falfe Philofophy j tior
feared by the ftperftition of a counterfeit Keligion.

From which words, I conceive that I may colleft this Do"
ftrine, namely, That in the Boob of the Wife of this VVorld,
tfaere are containqd fome Natural truths that are folidly demon-
flrated, and others again that are barely taught j and that as fo
thp firft fort, it is the OflSce of wife Divines to (hew that they
arc not contrary to the Sacred Scriptures j As to the reft, taught?
but not ncceffarily demonftrated,!! they fliall contain any tW^S
coii^ary to the Sacred Leaves, it ought to be held undoubtedly
feJf<? , and fuch ic oiight by all poffible waies to bedemon-

If oh^.Jiefor<5 Natural Coflclufipns veritably demonflrated?

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2°K.B. 9,163

J» Philosophical C ON TROvKRSiEs.

443

not to be poftpofed to the Places of Scripture, but that it ought
to be (hewn how thofe Places do not interfer with .the faid Con-
clufionsi theh its neceffary before a Phyfical. Propofitioii be
condemned, to (hew that it is not neceffarily denjonftratcd , :.ipd
this is to be done not by them who hold it to be true,but by thofe
who judge it to be falfe; . ^And this feemeth yejry reafonable,
and agreeable to Nature ; that is to, fay, that, they may much
fflore eafily find the fallacies in a Difcourfe, who believe it to be
ftlfe, than thofe who account it true and concludent. Nay, in
this particular it will come to paffe, that the followers of this o-
pinion, the more that they (hall turn over Books, cxatnm,c>the
Arguments, repeat the Obfervations, and compare the Experi-
ments the more (hall they be confirnf»ed in this, belief. And your
Highnefsknoweth what happened to the late Mat^iematick |»ro-
fcfTor in the Univerfity oS fifa. Who betook himfclf ni his, old
age to look into the Do&tme of Cop^rnicu^y with hope that he
might be able folidly to confute it (far that he held it fo far to
falfe as that he had never fludied ir) but it was his f^taae,
that as foon as he had underftood the grounds.^proceeding,, and
demonftrations of Copernic,^, he found himfelf to be pcrfwaded^
and of an oppofer became his.moft confident Dctender. 1
might alfo nominate other r Mathematicians, who, being niQyed • p. cuWu. the
by my laft Difcoveries, have confetted it nccefsary to change the Jefuw.
formerly received Conftitution of the World, it not being. gbk
by any means to lubfift any longer.' .nh Oi .'.

If tor the bani(hing this Opinion and Hypothcfis out of the
World it were enough to ftop. the mouth of one alone , as it
may be' they perfwade them(elves vviho mcafuring others judge-
ments by their own, think it impoffible that this Doftrine (hould
be able to fublifi: and finde any followers, this would be very ea-
fie to be done , but the bulineis ftandeth othefwife = For to
«ecute fuch a determination, it would be nece(C»ry to prohibite
not oncly the Book of Copernkm, and the Writings of the o-
ther Authors that follow the fame opinion, but to mtcrdia the
whole Science of Jftro/iomy ; and which is more, to forbid men
looking towards Heaven, that fo they might not (cc Mars zad
Vonr^ at one time neer to the Earth, and at another farther off,
with fuch a difference that the latter is found to be fourty times,
and the former fixty times bigger in furface at one time than at
another i and to the end, that the iame Venus mig\it not be
difcovered to be one while round, and another while forked, with
tnoft fubtil homes ; and many other fenfible Obfervations which
can never by any means be reconciled to the P*(;/<»/«tf/cA.Syfteme,
•'"t arc unanfwerable Arguments for the CoptrmcM.

the prohibiting of Copernict*s hi* Book, now that by many
^ " Kkk 3 new

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2°K.B. 9,163

The Authority o/ScaiPTURE,

new Obfervations, and by the application of many of the Lear-
ned to the reading of hini , bis Hypothefis and Doftrine doth
every day appear to be more truej having admitted and toleratca
it for fo many years, whilft he was leffe followed, ftudied, ana
, confirmed, would feem, in my judgment, an affront to Truth,
and a feeking the more to obicure and fuppreffe her, the v^oic
(he (hcweth her felf clear and perfpicuous.

The abolifliing and cenfuring, not of the whole Book, but
onely fo much of it as concerns this particular opinion of tnc
Earihs Mobility, would, if I miftake not, be a greater detriment
to fouls, it being an occafion of great fcaiidal, to fee a Po6"f^
proved, and to fee it afterwards made an Hcrefic to believe tt*

The prohibiting of the whole Science, what other would
be but an open contempt of an hundred Texts of the Holy Sen'
ptures, which tea;.h us, That the Glory, and the GreauiefTe <>}
Almighty God is admirably difcerned in all his Works, and
vinely read in the Open Book of Heaven ? Nor let any on<^
think diat the Lecture of the lofty conceits that are written ^
thofc Leaves finifli in only beholding the Splendour of the SuO>
and of the Stars, and their rifing and fetting, (which is the term
to which the eyes of bruits and of the vulgar reach) but ^^f^
are couched in them myfteries foprofound? and conceipts »^
lirae^ that the vigils, labours, and ftudies of an hundred and an
hundred acute Wits, have not yet been able thorowly to div^
into them after the continual difquilition of fome thoufands <J*
years. But let the Unlearned believe, that like as that whi^"
their eyes difcern in beholding the afpeft of a humane bodyi
very little in comparifon of the ftupendious Artifices, which an
ex^ifite and curious Anatomift or Philofopher finds in thefa^c
whenJie is fearcbing for the ufe of fo many Mufclcs, Tendorisj
Nerves, and Bones j and examining the Offices of the Heart,
and of the other principal Members, feeking the feat of the vi-
tal Faculties, notifngand obferving the admirable ftruftures or
the inftruments of theSenfcs, and, without ever making an eno
of faw^ifying his curiofity and wonder, contemplating the Re-
ceptacles of the Imagination, of the Memory, and of the Un'
derftanding i So that which reprefcnts it felf to the meer figu^
is a« nothing in comparifon and proportion to the ftrange
ders, that by help of long and accurate Obfervations the Vvi*'
of Learned Men difcovereth in Heaven. And this is the fub-
fttnce of what I hadtoconfidcr touching this particular. .

In the next place, as to thofe that adde, That thofe Na^^^
^«^p<ifltions of which the Scripture ftill fpeaks in one ec^^'ft^f^
tenour, and which the Fathers all unanimoufly receive in
famcfettfe, ought to be accepted according to the naked an

/» ?H iLOSOpicA L CoNTROVlRSI ES.

literal fenfe of the Words, without gfofles and interpretations i
and received and held for rooft certain and true ; and that coii-
fequentlytheMobility of the Sun, and Stability of the Earth,
»s being fuch, are de Fide to be held for true, and the contrary
opinion to be deemed Heretical; I propofc to confidera-
tion, in the firtt place. That of Natural Propofitions, fome there
»re,of which all humane Science and Difcourfe can furnifli us
otJy with fome plaufible opinion, and probable conjeaurc ra-
ther than with any certain and damonftrativc knowledge ; as for
example, whether the Stars be animated : Others there arc, of
which we have, or may confidently believe that we may have,
by Experiments, long Obfervations, and Neccffary Demonftra-
tions an undubitable aiTurance ■■> as for inftance, whether the
Earth and Heavens move, or not ; whether the Heavens arc
Spherical, or otherwife. As to the iiift iort, I doubt not m the
Icaft, that if humane Ratiocinations cannot reach them, and
that confequently there is no Science to be had of them, but on-
ly an Opinion or Belief, we ought fully and ablolutely to com-
ply with the meet Verbal Senfeof the Scripture: But as to the
other Pofitions, lAould think (as hath been fa,d above) That
WeTre fiS^ toafcertainour felvesof the fad .t felf, wh.ch w.ll
affift us in finding out the true fenfes of tje Scr.ijires i wh.ch
Ihail moft certainly be found to accord with the fad demonftra-
icd for two truths can never contradia each other. And
ites'ltaketobcaDoarinc orthodox and undoubted, tor that I
finde it written in Saint who fpeaking to our point

of the Figure of Heaven, and what it is to be believed to be in
regard that which Aftronomers affirm concerning it feemeth to
be, contrary to the Scripture , (they holding it to be rotund,
and the Scripture calling it as it were a ' Curtain, dcterm-
neth that we are not at all to regard that the Scripture contra-
dias Aftronomers ; but to believe its Authorjty, if that which
they fay fcallbefalfe, and founded^only on the conjeauies of
humne nfinnity : but if that which which they affirm be pro-
ved ndubitable Reafons. ^^s.Holy Father doth not ay
that the Aftronomers are to be en oyned, that they themrdves
rcfol ingtnd renounci their Demonftrations do declare their
Conclulon to be falfe , but faith , that it ought to be de-
tnonfttated, That what is faid in Scripture of a Curt n is not
contrary to heir true Demonftrations. Thele are his woras .
(*) BVJotoyjeSi ; ti'. doth it appear, that the f^^^^^^^

Who ftrctchethout the Heaven as a Curtain, maketh
«»« agLji thofe rch, maintain the Hca'.ens to be ,n fgnrc of a
Spbtr, /utit be fo, if that be falfc whjhthey affirme : For
*bathtr»tbrPhich\isffokf by Divine Authority, rather thai

44T

* PiRc', a'Skinift
the Original , buc
in our Biblct a
Curtain*

f h) Sed ait dU"
^uis^ <jHomod§nom
eft cmrariMmiiti

rd Ceeh tribunt^
^M»d fcriftnm efl
in Libru Nefrkt

Qui extend it Cae-
lum, ficutpellemit

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

4^^

Tbe Autboritj o^§q a i,? T u r i

Stt fane contr^iri- thdt lophich procccds from HHrad?H :h^^^ BHtif .^cr^admn^^
'""^f'.ff'^fl"' '^: ^wrtf thej/. jhonld be ^bje to frofuc ih^f Pofitionfy fuch Bx^erimentj
as puts if, out of ^H^i^n^ it k to y ^.ro'uec^^^ 'what is /^^.^^J

quod ilU dicant :
ijoe cnim vernm

eff-, (j(€:d D'vifia Scripture concerning a

ptiu4Ciu.milhd, their mamfeft Keafons, . . ^ I.Jy^;.
ejund hnmana in- Hc prp^ccedeth aftci'wards to a4tnoni{Liis tnat we ought to oc
lZ%orTmd lefs careful and obfervant in reconcile of Scripture

taiihm iiu docft- with a den^onftrated Natural Propofition/:^ w th anotbef

nolefldJ*Peiic lt' wh^ch vvc may afllire our felvcs that we canT have no knowledge
Unm^ veru tiiis pr &iencc by humane demonjftrati.pn, is. vcry^rcfcrved in '(iete^^^^
r^^iombus mnejfc fining what IS to be beheved, as we fee by th^ which he vvri-
teth in tlje qnd of his fecond Book, .<^e Genefi ad Litteram '^ i^tf^',
{i) Sluodiicn in in2,whttlier theStar3 are to be believed . am mate ; ( i^.Which^
pr4'»ti facile r.on payficular. dlthou^h (at pre fen t\ iu anno t eafify be comprehendedx.

C0ntr4rmm.

poffi( comprehend'] y r r - r' "i n ' • - ' r n i n ' i o '-'-^ '

arkitroT tamefi.in y et 1 J Hppoje m our farther F the Scriptures*

procfjf(t_ traSian- fff^y Pieet tpith fow, more pertinent plac-es^ upon which it tfitlt

Aarum Script (*r 4' • . # ^ ^'.^ r' 'r ^\ */r

im^opportumofA Q? permttt^dus {if not to deter mm any thing for certain, ji^t J f^^

c4pop occHrre- fuggefi fqmen>hat concerning tbk matter ^ according to the di^^^ff

7e\}ecZdlmSxn- ^f^^.^^^^^d 4^thority..^,*BHt nov^v^ the moderation ofpioUs'j^ra'Z^^^y.

M^mtatis being atjp(ties ohjer'uedy'vve ought to receive mthingr

litteras, etfinon ]^ doubtfulpointjeaft'p^^^^^^ We rejeSt that outof reTpcBto^^

tUi^Hid,t amen ere- aur ^rroHiTy u'vbich hereafter Iruth may dij cover , to be tnjy.

derc lictbit.mnc ^^jf^ repHQHant tp4hi Sacred Volumes of the Old andVe^vif X^fl

fempermod:raito- Jtament.. ' ..Vi.-* j ! -

ne pUgr.^vitatU, ^ this and Other places (if I deceive riot my felf^ the intent
of the Holj/ri^athers a|^eareth to be. That in Natural queftions,
and which are not ^/^ f /^/^5 it is firjft to be confidered , whether
they be indubitably demonfirated, or by fenfible Experiments
known .5 or \yhether fuch a knowledge and dcmonftration is to be

mer,tivetert,,f,ve. bad i vvllic|l having p^t^i^^^^^ gift of ^0^1 v

mvinMrmdoef- ought to bq, apply ed to find put the true Sences of the Sacred r^"
fe pofit aeverfum, pre? in thofepjaces, which in appearance might fcem to fpeak to

tamen propter a- p- ■ ■ -J'* , xxn- i .11 n • ft • ^ ' J'^tn

morem mftri er- a coutrar/ nicaumg : Which Will unqueftionably be pierced into
roruyodntmiu. Pfudent Divines, together, with the occafipns that moved the
Gcn.'^^i Ltftera- Holy Ghoft, (fof our cxercife, Or for fome other reafon to me un-,
ram,\ih,i,i„ fi„(, known) to veil it felf fometlmes under words of different fig^^'
fications. ^
As to the other point. Of our regarding the Primary Scope oi
thofeSacred Volumes, I cannot think that their having fpok^/^
^Iwaiesin the fame tenour , doth any thing at all difturb this
Rule. Fqj. if it hath been the Scope of the Scripture by way
vowdefcention to the capacity of the Vulgar ^^Y time, ^^^^J

ftihtt Credere dere
ehfcura temere
debemm ; ne forte ^
^uod po y?f 4 verh as
fatefeceric^cjuAm^
^ii ' LtbrU Sah^
aia^ ftvg Te^A'

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Images reproduced by courtesy of the Royal Library, Copenhage
2°K.B. 9,163

In Ph ILOSOPH IC AL

prefsa Propoficionin words, that bear a fenfe different from the
EffenL of?he iaid Propof.f.on why might «
the fame, and for the fame refpeft, asoften as had jc^^l o^^^
fpcakof the fame thmg? Nayl conceive , that to have do^e
oiher w.fe, would but have encreafed the confufion , ^^^^^^
nilhed the credit that thele Sacred Records ought to have ^
moneft the Common People. , ^, . f ,r„ ana
Again, that touching the Reft M.^'^^" ^J^^^./^^:;.
Farr^ ir necelTarv, for accommodaaon. to Popular t.apa
;« ffc ha'w^^^^^^ «f Scripture .m.

F^^Lh expe^^^^^^^^^^ For chat even toourdayes

KcfaS^^ "^^"^^ OpmronuponRea-

Fonf tl a if hey were well weighed and examined , vvould be
Cndt bltU trivial, an/upcn Experiment -her whoU
Ivfalfe or altogether befides the purpofe. Nor is it wortn
m l go aSt to remove them from it, they beu.g nicapab e
ofthe contrary Realons that depend upon coo exqu.fite Obler-

v:i:,Tnd tJo fubtil J^;teof fh^^^^^^^

aions, which,fortljecon^^^^^^^^^ 3^^,,,,^ J

an Imagination. .^''"'^"^ p, ' . be more than certain

Heaveu%nd Motion ofthe Earth IhouW^^^^^^

Tia^l^t::^^^^^^^^ vulgar to

Sfthe^on rary : For that of a thoufand ordinary men that
o^to be queSned concerning thefe particulars, its probab c
tLt tLere will not be found fo much as one that will not
fwer that he thinketh, and fo certainly he doth , that the bun
move h nit Earth Itandeth ftiU. But yet none ought to
take this^c" mmon Pop-lar Affent .o be .;^^yJZT.:L^
truthof that f^turg^h^Tinds'^VmoIvesby which they
thefe very men touching cne g ^ j ^ the other lide

are induced to believe in that man ner '^"^^^^i^^^ipe^fwade
fliouldhear what Experiments ^^""^ femo^ a ^j^^j.^
thofe few others to believe the contraty^^^ "^'fud he former by
Utter to be moved by ^^^.^^^''^.^'J^^l' occurrences. That
fimple appearances, and vain and Sun , and Heft

therefore^ wasnecefTary to ^'ffig'^.^^Xhe Vulgar {hould be
to the earth, left the niallow "Pac»ty

contumacious,

confounded, amufed, and rendred °bft'""^ j ^bfolute-
in giving credit to the princ.pal Articles, and w^ ^

lyeieJJ^insfufficienUyobviou^. And t^^^^^^

do, it is not at all to be wond.ed at. th^^^^^^^^^^^
denary wifdom fo done, in the Di vin P ^

Butl will alledge further Tha^^^^^^^^^ Opiitl of thofe times
Incapacity ofthe Vulgar, but toe cuu f ^^^^

The Authority 0/ S c Pv i p t u r e

made the Sacred Writers, in the points thac were not neceffary
to falvation, to accommodate themlelves more to the received
ufe, than to the true Effence of things : Of which S. Hierom
(k) Quaji mn treating, writeth : ( ) As if many things n?erc not fpoken m
mult a in Serif tw the Holy Scriptures according to the judgement of thoje times
]t%ttiiZ' ^f^'^l' ^'''y ^^'^ ^'^^ '^^^ according to that n^hicb

rtem iHiw ttmpo, u truth Contained. And eUewhere, the fame Saint: (/) It is the ch-
c^lifjlZ^r^m^ P^^f^r Pen^men of Serif ture, to deliver their Judgments in
reiveritodconitne' many things^ according to the common recei'vcd opinion that their
^4^p.Hicro.mc. times had of them. And' S.Thomas Aquinas m Job upon thofc

2o.Jercm. J i^i ^ %iAit

{\) Confuetudi- wolds, Qui extendit Aqmlonem fnper ^^acnum ^ appenai^

nis scr$ptftrarum Xerram fiiper nihilum: Noteth that the Scripture calleth that

mihtarumTJrum fp^ce VacHum and Nihilumy which imbraccth and invironcth the

jicndrret Hi/ton- Earth, and which we know, not to be empty , bat filled with Air^

tZpJeZTtn'- NeverthelefTe, faith he, The Scripture to comply with the appre-

crgdebAtur, In hen li OH of thc Vulgar, who think that in that lame fpace there

'^**^"d TT^om^^ in nothing, calleth it Facuum Sind Nihilum. Here the words of

cap. a5Job.v.7. S. Thomos^ Qjiod de fuperiori H^mifph^rio Cceli nihil nobis ap'
paretj nifi fpatium aere plenum^ quod ^vulgares homines reputafit

Vacuum i loquitur enim fecundum exifiimationcm ^uulgan^ff^
minum^prout ejl mos in Sacra Scriptura, . Now from thi^ P'^^^
I think one may very Logically argue, That the Sacred Sciip^^^^
for the fame refpefi had much more reafon to phrafc the Sun i^^'
veable, and the Earth immoveable. For if we ftould try the ca-
pacity of the Common People, we fliould find them much tno^c
unapt to be perfwaded of the {lability of the Sun, and MotioJ^
of the Earth, than that the fpace that environeth it is fu)l of A^^'
Therefore if the facred Authors, in this point, which had not 1^
much difficulty to be beat into the capacity of the Vulgar, have
notwithftanding forborn to attempt pcrfwading them unto it,
muft needs feem very reafonable that in other Fropofitionsin"^"
more abftrufe they have obfervcd the fame jftile. Nay Copertttcf^
liimfelf, knowing what power an antiquated cuftome and way
of conceiving things become familiar to us from our info^^^X
hath in our Fancy, that he might not increafe confufion anddti-
ficulty in our appi ehenfions, after he had firft dcmoiiftr^^^^'
That the Motions which appear to us to belong to the Sun, or to
the Firmament, arc really in the Earth , in proceeding
wards to reduce rhem into Tables, and to apply them to ufe, '^^
calleth them the Motions of the Sun, and of the Heaven that is
above the Planets ^ cxprefly terming them the Rifing and Set-
ting of the Sun and Stars i and mutations in the obliquity^
the Zodiack, and variations in the points of the Equinoxes,
Middle Motion, Anomalia^ frofttjaph^refis of the Sunj and iucn
other things which do in reality belong to the Earth : But he-

/»PhI L OSOPHIC AL CONTROVERSIES.

44^

caufe being )oyned to it, and confeqiiently having a fliare in cve-
of its motions,we cannot immediately difcern them in her, but
«re forced to refer them to the Ccleftial Bodies in which they
Appear ^ therefore we call them as if they were made there, where
they feem to us to be made. Whence it is to be noted how ne-
neffary it is to accoitniodate our difcourfe to our old and accu-
ftomed manner of undeiftanding.

That, in the next place, the common confent of Fathers, in re-
ceiving a Natural Propofition of Scripture , all in the lame fenfe
ought to Authorize it fo far, as to make it become a matter of
Faith to believe ic to be * fo, 1 ftiould think that it ought at moft ^ j^^niely ' ac
be underftood of thofe Conclufions onely,which have beenby cording to ihc Lit
the faid Fathers difcuffed, and fifced with all poffible diligence, ^"^IS^^e*
and debated on the one fide, and on the other, and all things in
the end concurring to difprove the one, and prove the other. But
the Mobility of the Earth, and Stability of the Sun, are not of
this kinde ^ For, that the faid Opinion was in thofe times total-
ly buried,and never brought amongft the Queftions of the Schools,
and not con(idcred,much lefs followed by any one:So that it is to
believed that it never io much as entered into the thought of
the Fathers to difputc it,the Places of Scripture^thcir own Opinio
^nd the aflent of men having all concurred in the fame judgement,
vvithout the contradifiion of any one , fo far as we can finde.

Befides, it is not enough to fay that the Fathers all admit the
ftability of the Earth, &c. Therefore to believe it is a matter of
f^aith : But its neceffary to prove that they have condemned the
contrary Opinion : For I may affirm and bide by this; That their
"oc having occafion to make fatisfaftion upon the fame , and to
^ifcufs it, hath made them to omit and admit it , onely ascur-
^^'^t, but not as I'^folved and proved. And I think I have very
good Pveafon for what I fay For either the Fathers did make
^^flcaion upon this Conclulion as controverted, or not : If not,
then they could determin nothing concerning it; no not in their
private thoughts j and their incogitance doth not oblige us to
|"^ccive thofe Precepts which they have not, fo much as in their
^^^tentions enjoyned. But if they did refleft and confider there-
they would long finCc have condemned it, if they had judged
't erroneous iwhich we do not find that they have done. Nay,after
that fome Divines have began to confider it, we find that they
**^ve not decm'd it erroneous^ as we read in the Commentaries of
I ^idacHs a Stumca upon Job.n^ Cap.9y^-6.oi\ the vvords,2«i com^

■ , ^^^'vu I err am de locofnOyScc, Where he at large dilcourieth upon

■ ^^^^opcrnica» Hypothecs, and condndcthy That the Mobility
m ^fthe Earthy is not contrary to Serif ture.

ft Withal^ I may juftly queftion the truth of that determination,

ft ^^mely, That the Church enjoyneth us to hold fuch like Natural
I LI I CQn-

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

45?

C9H€il.Trul.Stf.
4- '

(*) His re-
fpuudec , ntul um
fuyiilittr^ & UlfO'
rif>fis rsiionil^tuy
iftAferejHin , ut
vere percptatftr^
Htrumita^ non
staff, ^utfttts tn-
eundu at<jf*e tra-
itandu , »eC mthi
jam temPut r/?,
fiectllu efe debet y
^nos ad f^ltttem
fuam^ SanElAEc
cleft€ necejfartam

nt Hit at em

fftff* inftrmari,

(m)NoH Solem^fed
Primttm Mobile
immotum c&ttfii-
tifei Dionir.
Areop.

Omni^ cor-
fornCale/lia ^im^
mota jHbfiitijT*'

The (Authority 0/ Scripture,

Conclufions as matters of Faith 5 onely becaufe they bear the
ftamp of an unanunous Interpretation of all the Fathers : An"
1 do luppofe that it may poffibly be, that thofe who hold in this
manner, might poflibly have gone about in favour of their own
Opinion, to have amplified the Decretal of the Councils , which
I cannbt finde in this cale to prohibit any other, fave onely ,
verting to Senfes contrary to that of Holy Church , or of tht
concurrent confent of Fathers^ thofe places , and thofe onely that
do pertain either to t aiih or Manners^ or concern our edifcatio»
in the Do^^rine of CLnJi/anity : And thns Jpeal{S the Council (ff
Trent. Seff But the Mobility or Stability of rhe Earth, or
ofthe Sun, are not matters of tajth , ror contrary to Manners,
nor is there any one, that for the ftablifliing ot this Opinion?
will pervert places of Scripture in oppoficioii to the Holy Church,
or to the Fathers : Nay, Thofe who have writ of this Doftrinc,
did iiever make ufe of Texts of Scripture ^ that they might leave
it ftili in the breafts of Grave and Prudent Divines tJ interpret
thefaid Places, according to their true meaning.

Aad how far the Decrees of Councills do comply with the Hp-
ly Fathers in thefe particulars , may be fufficiently manifeft? ^
that they arc fo far from enjoyning to receive fuch like Natura
pancluiions formatters of Faith, or from cenfuring the contrary
Opinions as erronious j that rather refpefting the Primitive an
primary intention of the Holy Church , they do adjudge it"^'
protitahle to be bufied in examining the truth thereof. •
yourHighnefs be pleafed to hear once again what S. Augujli^f
aniwers toto thofe Brethren who put the Queftion , Whether
be Itrue that Heaven moveth, or ftandeth ftill? (^*) To thefe I
aefjt^er^ That Points of this nature require a cur ions and prO'
foun^ examination ^ that tt may truly appeaf'^ rvheth^f they he
trrue>ot fdlfe ''i , awork^ iry^onfijient with my leafure to '^^^^^'
taks argothoroxp with ^ nor it any rvay neccffary fo^ ^^^^r^
whom rve defire to inform of the things that more neartjf
concern their own fal<z/ation and The Churches -S^'
Hi^fit.

But yet although in Natural Propofitions we were to take tn^
refolution of condemning or admitting them from Texts of Scf»'
pture unanimoufly expounded in the fame6enfe by all the f^'
thers,yet do 1 noc fee how this Rule can hold in our Cafei>for ^^^^
upon the fame Places we read feveral Expofitions in the Fathef^^
(,m) DionyfiHS Areopagita faying, That the Frimnm Mobile^
nottheSunJiandjiiU. Saint A ugujl in e is o( the fame Opi^^^^^^
C«> All the Celepal Bodies were immoveable. And with the
concurreth Abulenfts. But which is more, amongft the ]^^!\
Author® C>whom Jofephns applauds) fome have held , CO ^

Z/^PhilosophicalGontrcve^sies. 45t

Tfcc Sun did not really ftand fiill, hut fecmed foto do, during the SoUm re*
fhort time in rvhub Ifrael s,a-je the overthrow to their Enemies, v^r^non fubfittp
So foi the Miracle in the time ot He%ekjab,tanlfis i^nrgenjis is or

pro hrevi tempore^

Opinion that it was not wrought on the Sun, but on the Diall. mrajuod rfr^eii-
But that, in (hort, it is neceffary to Gloffe and Interpret the '^J^^/Z^ii
Words of the Text in Jojhna , when ever the Worlds Syftemc fum^e.
is in dii'putc, 1 (hall fliew anon. Now finally, granting to thefc -C^Po?.
Gentlemen more than they demand, to wit, That we arc whol-
ly to acquiefce in the judgment of Judicious Divines, and that
in regard that fuch a particular Difquilition is not found to
have been made by the Ancient Fathers, it may be undertaken
y the Sages of our Age, who having firft heard the Experiments,
Obfcrvations, Rcaibns, and Demonftrations of Philolopners and
Aftronomers, on the one fide, and on the other (feeing that the
Controverfie is about Natural Problems, and Neceiiary Dilcfn-
^^'s^ and which cannot pofilbly be otherwife than in one of
^he two manners in controverfie) they may with competent cei-
tainty determine what Divine Infpirations Oiall diftate to them,
fiutthat without minutely examining and difcufling all the Rea-
"^ons on both fides^ and without ever comming to any certamty
of the truth of the Cafe, fnch a Refolution fiiould be taken, Is
not to be hoped from thofe who do not ftick to hazzard the Ma-
jefty and Dignity of the Sacred Scripture , in defending the re/
putation of their vain Fancies ^ Nor to be feared from thofc
^ho make ic their whole bufineffe, to examine with all in-
^enfncfs, what the Grounds of this Doftrine are and that only
inanHolv Zeal for Truth, the Sacred Scriptures, and for the
Ma)eay, 'Dignity , ai d Authority , in which every Chriftian
ihould indeavour to have them maintained. Which Dignity,
^hofceth not that it is with greater Zeal defined and procured
h thole who , abfolutely iubmitting themfclves to the Holy
Church, defire, not that this, or that opinion may be prohibi-
^^d, but onely that fuch things may be propofed to conlidera-
^ion, as may the more afcertain her in the lafeft choice, than by
^hofc who being blinded by their particular Intereft, or ftimula-
by malitious fuggeftions , preach that (he fliauld without
^ore ado, thunder out Curies, for that (he had power fo to do :
confidering that all that may be done is not alwayes conve-
^i^nt to be done. The Holy Fathers of old were not ot this
opinion, but rather knowing ot how great prejudice , and how
^^ch againft the primary intent of the Catholick Church, it
^^uld be to eo about from Texts of Scripture to decide Natu-
'^l^onclufions, touching which, either Experiments or neceffary
Demonftrations, might in time to come evipce the contrary, of
^hat which the naked fenfe of the Words fdtihdeth, thty have

L 1 1 a not

^"^^ (Authority 0/ Scripture,

not only proceeded with great circunifpe&ion, but have Icfc the
. following Precepts for the inftruftion of others, (p) p^^^^^^^

fclru,Itl{'ue/r,^' obfcnre aadrefmte from our Sights if we come to read any thing
^'/rm''*^''H7Z'c ^''^ of Sacred Writ^ that^ with a Salvo to the Faith that m ha^e
}fT^u\fi^m^vL imbued^ may correffond with feveral conjirnBionSy let ns not fo
rAiegerimtu, far re throTP our fel<ves upon any of them with afrecipitoips O'^"
^/l^JZlf^^^^^^ il^^^ if Perhaps the truth being more diligently fear cVt

iiu atatit altii ^a- into^ it fhohld jnfily fall to the ground ^ we might fall together
Zlt:Z:Z ^^th It : and fo fhew that we contend not for the fenfc of Dimnc
prAcipiti afjirmM- ScriptHres^ but onr owHy in that we would have that which ^
t,one ita projtci- to be the fenfe of ScriptureSy <v<uhen as <vve pould ra-

dmm , Ht ft foftc . , r 1 o I

ailigemtHs d>[cu\- ther defer € the Scriptures meaning to he ours.

[4 Veritas (a reUe

iMhefaElaverit-, corruamus : non fro fentCKtU 'Diviftarum Scrifturarum ^fcd prg mfira tta dimicantes , t^f
veltmKs Scrtpturarum tffc^ qH£ nofira efiy cum potttu egm qt*£ Scrtpturnrum f/, no^ram tffe vellc debe4mtU»
DiVus Auguliin. in Gen. ad Licteram, hb. 2.c. i8- & fcq.

He goeth on, and a little after tcacheth us, that no Propofr
tion can be againfl: the Faith, unleffe firft it be demonftrate^
(q) Tamdtts ncn f^jf^ . faying, Qi) Tis not all the while contrary to Faith^ until
t^TsUc!^fer. difproi;ed by mofl certainTruthywhich if it fljouldfo be.thc m
tifi^a reffilMtHr. Script ure affirm' d it not, but Humane Ignorance fnppof^^
pTrtJoJho^cZ Whereby we fee that the fenfes which we impofe on Text^«JJ

and not according to the found of the words, that may f^^^
true to our weakneffe , to go about? as it were, to force N^'
ture, and to deny Experiments and NecelTary Demonft^^'

tions.

Let YourHighneffebeplcafed to obferve farther, with ho^^
great circumfpeftion this Holy Man proceedcth, before hc^ai-
firmeth any Interpretation of Scripture to be furc, and in uic
wife certain, as that it need not fear the encounter of any ^\
culty that may procure it difturbance , for not contenting
himlelf that fo me fenfe of Scripture agreeth with
(r) 5» 4«ftw ftration, hefubjoynes. (r) But if right Keafon Jhall dem'*
»Z7tm>n. firate tbk to be true, yet k it qHefiicnahle whether in thefc tPOt^^^
flrmerit., tdhnc of Sdci ed ScriptHre the Fen' man would have this to be itttdi
'ZXc'tMllpod, orfomwhatelfe, no leffetruc. And in cafe the Cont^^^
verbii SstnnoTHm of his Words Jhall pr 07/ 8 that he intended not this, yet w^'*^
^!^feluri vail'. ^^^^ ^'^^^^ would ha^ve to be underfeoodbe therefore falfh
ri>, 4» mofii true, aad that which is more profitable to be ^noui/n-

iindnonmtnmve' , r r i- J a nod 'f/^

rt(fff. Sj^''^ C€tefAcontexth fermonu non hoc eumvolftipfrobavifity rM>nideo faljum erit n
iutellil* voitfityfcd vtrum, & tjHod miliw cogptofcdtur.

But that which incrcafcth our wonder conccrning^^^.^^^

/« Philosophical CoNTnoYERSiES. 453

r r a- «,KprewVth this Pious Authour proccedeth, is, Sfr.p(«r*,
cumfpeaion, wherewith t"' ,^ j Demonftrative

that not trufting his oblerv.ng, that o the reft "i'

R^^r^nc on<1rV,j- fenfe that the words ot icnpturc auu i 1 1.. „p»i«z'«-<f,
Kcalons, andthclcniei iubfeauent, do confpirc to ^dku/ %.M>'

of the Context both precedent ^n*^.'""*^?"" 5«,„r., d-

nr„„. tU^ f^m*- fhinP he addcth the following words. ^
prove '^^^^""^/^^^^^^^^ do not hold forth any thing that ^
(f ) But tf the Loniext^o i, y.t remains to enquire, .Wp««#-«-.-

difproie thk to be the Authors Senfe tt yt ^^^"'"^ .cfolvinfi
Whethertheothermaynotbe tntenae J . that he r«^,'/.W«mr:

toacceptofoneSenfe,orre,ea another, b"j hink.ng n

/A)«/^er ffcfcfW J h,it thinking that he r«^ ,'/.w«mr:

toacceptofoneSenfe,orre,ea another, hink.ng n ^ ^

^ ij r f.ffiripiit caution, he proccedeth- ( «; Z*'" 'J

could never ufe fufficient "ution, f ■ t/*«/'te^' ««»r mJ«»r.j!

/o /;«^. that the other may be aljo meant t <v

i.1 . ■ i , ^ I. I J l,^«,;>t,>aand ■■, or which in frooaomiy u ^^^^ cinHmfi<«,-

fo be n^efinde that the other may be aljo meant t <v

I r.j, U.^^^ufd havetofiand torwhich in frooaoiwy "
ti>htch of them hetPOHld \.,'ircHmliancei on both fides bt ,ia MragmL

may be thought to am if the true "''""'J^f"ir {^is his ( « ) ^-W'
y„ I J t ^ Uftlv iiitendinetorendera Keaion oi uns «»

And laftly, ""^f "§ . „,en cxpofe the Sen- r^d.

Rule, by {hewing ustowhat P^"'' ^^'^ V cV«„r«*-
Ptures and the Church i who, more t^lpcCting ine '

A«.homy beyond "S^"* J^ ^h K^W- -"V. S^Vt
fubjoyns the enfumg woras , w liberty, which feme r««, ««« w,-

fuffice to reprefs and moderate the excd^^^^^^ S.,^^ ^

think that they may ^ f„Uy nnderfiand a ku. .™ dr

times falls out, that a l*'\f''"^2dth rkofthi^ ,.n.f^nn.,i,N..

■r» _«i«/r •fii' E/irtfo, Heaven^ ana toe reji "i ,„ru MimaiiHm,

J'o'nt concerning the tart^^^^^^^^^^ ^ jy.^ances of f.„,,,„,Uf.d.J,

Elements ; the Motion, C-^^^^r" J^^ ^ j^y^„^ ^he Ke'i^olHti- ''«;»/-'^
ons of Yea s j T;^/;' ^ ^,y,„^ ,k rijf

H^^lfndeaChrifiianfoM^^^^^^^^^ ^ J^^,^,

ters ; as if they were according to . Uughter, fee- - -

L- V K D Uith\ Ccarce able te contain i"!^^ ■>} . fumiHm

him (4* the Pr0'verbjattb)jc ^^^^ ^y^^ hrifiJis.Uuera,

inghim fo far from the UarK^ory^^ Anthers (honld be hi^cumM -t"

; nLl^ hp Uuvht at.but that our /imam j l,rur, qmUta i»-

in an erronrfiould be '""^"^ ' . r r^„, Ofinion,attd to l^,^, „
thought by them that are mthoit, to ^ oj toej j

the great frcj^^dice of thofe^whofefal^atio^^^^^^^^ C.U,r.
Chnft.ans in that mattcr.^M^ they tbemj

fiaiandM thereupon ^1^;^!^^^^ K^furreS^on of fr^f-t^I

ho^^ pall thefe Volumes be f f ^^^^T^^^ \- dom of He.^e«. retur.f.d.ua ^

^^^^U^^^^ DeLflrat^on, ^-fl^^-

^vhen,a^ to thefe Points ^^hrch ad^ t oj p j ^^^^^^^^^ ,..fj ^^^^^^^

yndonhted ^^^fons ^they^^^;^^^^^

f»4m de nofiru Uhru ^S'^'^^'j \ ^ .^jn exmirtivcl Mtmu r^tfombm F r

UUmsitcr fHt4Virin( tp eonjcrtftos.

ceteris^ etiam no»
Chrijhwtm it a no»
verit, Mt cifttffima
ratfonevelexperi-
entik teneat. Tmr-
fe amem eft nimis
& pgrMciofum^ 4C
mtiximc cteucn-
dnm , nt Chriftin*
num de hisrehm

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B.9,163

4^4

(y) Qnid e»irn
molefltA^trtfiiAij''*
itigerAnt prudenti-
hiu fratribu* , tc
nerartj p^dfumpto-
rts , fAtis dxinon
fotefi y CHtn , A
^nandodefalf-*^
prMVd op'tnione [uA
reprehetidt & con-
Viptcicdperint, ab
its ejui noftrfirnm
librorum auHort-

f4lfiiate dtxerunt,
eofdnm libros 54k-
Uss , undetdpror
ketit, proferreco-

tefiimonium vdlt-
re arbtirAntiir-,
multa itidevtrb*
pronnncUnt ^

^U4t loqttuntHrt »«-
tjHcdt qmbfu 4'

The Authority o/Sc ri pt u re

And how much the truly Wife and Prudent Fathers arc dif-
pleafed with thefe men, who in defence of Propofitions whicti
they do not underftand, do apply, and in a certain f^^^f P''^'^
Texts of Scripture, and afterwards go on lo encreafe their nri
Errour,by producing other places lefs underftood than the lor-
mer. The fame Saint declareth in the expreffions following '
(x) What trouble and forrowweak nnaertak^ers bring upon
their knowing Brethren, is not to be expreffcd ; finte when they
begin to be told and convinced of their falfe and unfound Opinion^
by thofc who have no refpeSl for the Authority of our Scriptures,
in defence of what through a fond temerity, and moft manifefifal-
ftty, they ha^e urged; they fall to citing the f aid Sacred Book^
for proof of It, or elfe repeat many words by heart out of them,
which they conceive to make for their purpofe not knowing
either what they fay, or whereof they afrm.

In the number of thefc we may, as I conceive, account thole,
who, being either unwilling or unable to underftand the De-
monftrations and Experiments, wherewith the Author and fol-
lowers of this Opinion do confirm it, run upon all occafions to
the Scriptures, not confidering t hat the more ihcy cite them , and
the more they perfift in affirming that they are very clear , and
do admit no other fenfes , fave thofe which they force upon
them, the greater injury they do to the Dignity of them (it we
allowed that their judgements were of any great Authority) m
cafe that the Truth coming to be manifefily known to the con-
trary, ftioiild occafion any confufion , at leafl: to thole who are
feparated from the Holy Church of whom yet (he is very felici-
tous, and like a tender Mother, defirous to recover them again
into her Lap Your Highnefs therefore may fee how praepofterouf-
ly ihofePerfons proceed, who in Natural Difputationsdo range
Texts of Scripture in the Front for their Arguments ; and fuch
Texts too many times,as are but fuperficially underftood by them.

But if thefe men do verily think,& abfolutely believe that they
have the true fence of Such a particular place of ^Scripture, it mult
needs fallow of confequencc,that they do like wife hold fottcertain,
that they have found the abfolute truth of that Natural Conclufi-
on, which they intend to difpute;And that withall, they do know
that they have a great advantage of their Adverfary, whofe Lot it
is to defend the part that is falfej in regard that he who maintain-
eth the Truth,may have many fenfible experiments,and many ti^'
cefTary Demonftrations on his fide whereas his Antagonift
make ufe of no of her than deceitful appearances, Faralogifms^^
Sophifms. Nowif they keeping within natural bounds,&: produ-
cing no other Weapons but thofe of Philofophy,pretend however,
to have fo much advantage of their Enemy j why do they after-

wat
por
beh
the
to I

Out

the
the
wir
the

Hoi
be
the
Ch

fllG

otl

CCI

6e
kn,
f»c
ll><
in
ho
di

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

In P

H I LOS OP H

icAL Controversies.

455

ward
pon

coming to engage,prefently betake tiiemfclves to a Wea-
inevicable & dreadful to terrifie their Opponent with thefole
beholdina ofit?Butif I may fpeak the truth,! believe that thjiy a^fc
the firft that are affrighted, and that perceiving themlelves tinable
to bear up againft the affaults of theit AdverUry go about to hnd
out ways how to keep them far eno,.gh ofF,forb.dd.ng untajheto
theufc of the Reafon which the Divine Bount), had vouchfafed
theni,8c abufing the moft equitable Authority ot lacked Scrtptare,
ich rightly undcvltood and ^PPl^cd can never, according to
e common Maxime of Divines, oppole the Mamfeft Expert-
Oents, or Neceflary Demouftratiou^. But thefe mens running
to the Scriptures for a Cloak to their i.. ability to compreherid,
not to lay refolve the Reafons alledgcd agaioft them, ougtrt < 1 1
be not miftaken) to ftand them in no ftcad : the Opn.iou wtu h
they oppofe having never as yet been condemned by Ho.y
Church So that if they would proceed rvith Candor hey
fl)ould either by filence confcfs themlclves unable to h*"d^e luch
■ikepoin.,or^.ftconfideyh.

thers Knf- nnelv in that oi tne luyc?**" . . i r : ^^^^ ha Oi,

^tners, "ut onciy in^ Erroneous : But that il,is left to their
ccnfure a Pofitipn to be ° . ,q thereupon, member .ha.

freedome to diipute concerning us *f butTt»nn.«.
know^ne that it is impoffible th« a Propofition (hould at the
t ifJ be Trueand HereticaU they ought, I fay, to imp oy
themfelvesin that work which is moftp oper to them, name y
i. demonftrating the falfuy thereof : .^^ereby they may lee
Vw needleffethe prohibiting of it ,s, its falrfiood being once
^ifcovered, forthat none would follow it : or the Proh.b.t.on
would be lafe, and without all danger of Scandal. Therefore
firft let thefe t^en apply theinfelves to examine the Arguments •
ut icttneiemenapiMy leave the condemning of them

ot Copernictts and others , anu u„i„„„f.rh • Rut vet let

for Erroneous and Heretical to whom it belongeth . But yet Jet
r erroneous anu " , , j prec pitous Determina-

them not hope ever to Hnde lucn ram anu i^ic ^ - , .^r-

;&re:;t,fr«.rxr.;'if ow., .....

^^i dc faBo they are. ^^^^^.^^ ^^^^^

*hich none hath power) than without that certainty by condem-
''ing oncTart^o deprivi ones fdf of that aathonty of frccdome

The Authority 0/ S c r i p t u r s

to jelcft , making thofe Determinations to become neccffary,
which at prefent are indifferent and arbitrary, and reft in the
will of Supreme Authority. And in a word, if it be not pol-
fible that a Conclufion fliould be declaied Heretical, whilft we
are not certain, but that it may be true, their pains are in vam
who pretend to condemn the Mobility of the Earth and Stabili-
ty of the Sun, unlefle they have firft demonftiated it to be itti'
poflible and falfe.

It remaincth now, that we confider whether it be true, that
the Place in Jajhuah may be taken without altering the pure fig'
nification of the words : and how it can be that the Sun, obey-
ing the command of Jo/hnah^ which was. That it Jhonldfiand
fiillj the day might thereupon be much lengthened. Which bu*
finefTe, if the Celeftial Motions be taken according to the Pt<>f^'
i«tfici^ Syfteme, can never any waves happen, for that the Su0
moving thorow the Ecliptick, according to the Oider of the
Signes, which is from Eaft to Weft (which is that which maketb
Day and Night^ it is a thing manifcft, that the Sun ceafing it^
true and proper Motion, the day would become fliorter and not
longer h and that on the contrary, the way to lengthen it would
bctohaftenanH velocitate the Suns motion •, infomuch that to
caufe the Sun to ftay above the Horizon for fome time,
and the fame p!ace,without declining towards the Weft, it would
benecc{rary to accelerate its motion in fuch a manner as that it
mi^ht feem equal to that of the Frimum Mobile^ which would he
an acccl^ratin^it^bout three hundred and fixty tiaies more than
ordinary. If therefore Jofhuah had had an intention that his
wards (hould be taken in their pure and proper fignification, he
would have bid the Sun to have accelerated its Motion ib, that
the Rapture of the Primnm Mobile might not carry it to the
Weft : but becaufe his words were heard by people which hap-
ly knew no other Celeftial Motion, fave th s grand and comnion
one, from Eaft to Weft, ftooping to their Capacity, and having
no intention to teach them the Conftitution of the Spheres, but
only that 'they (hould perceive the greatncls of the Miracle
wrought, in the lengthening ot itfe Day, he fpoke according
their apprehenfion. Poffibly this Confideration moved Diot^)'
fim Areopagita to fay that in this Miracle the Primnm Mo^^^^^
ftood ftill, and this- ftopping, all the Celeftial Spheres did oi
confequence ftay : of which opinion is S. Angufline himfelf?
AbHlenfis at large confirmerh it. Yea, that Jofhnas intention
Was, that the whole Syfteme of the Celeftial Spheres fliould
ft^nd ftiil, is colle&ed from the command he gave at the
time to the Moon, although that it had nothing to do in the

lengthening of the day j and under the injunaion laid up^^^

' MooH;

tLOS OPH 1 C AL CONTROVERSIES.

^oon, we are to underftaftd the Orbcs of all the other Planets;
P»flcd over in filence here,as alfo in all other places of the Sacred
S<^fipturcs i the intention of which, was not to teach us the Aftro-
"oinical Sciences. I fuppofe therefore , (iflbenot deceived)
'••It it is very plain, that if we allow the Ptolemaick, Sy fteine, we
""uft of ncceflity interpret the words to fome fenfe different from
'Iteir ftria fignification. Which Interpretation (being admo-
niflied by the moft ufefuU preceptJ of S. Auguftine) I will not
"firmto be of ncceflity this above-mentioned , fince that fome
"ther man may haply think of fome other more proper,and more
'greeable Senfc-

8ut now, if this fame palTage may be underftood in the Copcr-
"uan Syfteme, to agree better with what we read in Jojhuah,
*'th the help of another Obfervation by me newly ftewen in

Body of the Sun i 1 will propound it to confidcration , fpeak-
'"galwaieswiththofe fafeRefcrvcs i That lam not fo affeaio-
"^tc to my own inventions, as to prefer them before thofc of
'^''^er men, and to believe that better and more agreeable to the
'"teniion of the Sacred Volumes cannot be produced.
, Suppofina therefore in the firft place, that in the Muac^e of
hjhuah the whole Syfteme of the Celeftial Revolutions ftood
according to the judgement of the afore-named Authors:
^Qd this is the rather to be admitted , to the end , that by the
ft»yin2 of one alone, all the Conftitutions might notbecon-
^*»Unded, and a great diforder needlefly introduced in the whole
%rfe of Nature: I come in the fecond place to conliderhow the
Mar E|ody,although ftable in one conftant place,doth neverthe-
'efs revolve'in it felf, making an entire Converfion in the fpace
■^f a Month, or thereabouts ;as I conceive I have folidly demon-
•^flted in my Letters Pelle Machie Solari : Which motion we
fcnfibly fee lo be in the upper part of its Globe , inclined to-
wards ihe South and thence towards the lower part , to enclme
'awards the North, juft in the fame manner as all the other Orbs

the Planets do. Thirdly, if we refpea the Nobihty^ of the
$«n, and his being the Fountain of Light , by which, (as I necel-
f»rily demonftrate) no«,nely the Moon and Earth, but all the
Other Planets (all in the fame manner dark of thcmfe ves) become
'lluminlted j conceive that it will be no unlogicall Illation to fay,
^hat it, as the Grand Minifter of Nature, and in a certain fenle
tile Soul and Heart of the Wo.ld, infufeth into the other Bodies
^hich environ it i not onely Light, but Motion alio i by revol-
^■'"g ' in i t ielf : So that in the fame manner that the motion of
^ Heart of an Animal ceafmg, all the other motions of its
^embers would ceafe i fo, the Coriverfion ot^ ^the Sim cealing,
^••e Convcrfions of all the Planets would ftand ftiU. And though

M m m I

457

. On its own

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

8 The Authority of S g r i p t u k e

I could-producethe teftimonies of many grave Wiiters to pf<^^
the admirable power and influence of the Sun, I will content
felfwith one fole place of Holy jDi(?«i/i;^5 Areopagita'm his Boo^
(0 Lnxeitu colli' Piq^ink hominibm-, who thus -writes of the San: Q) ^^i^
^::^:;':^:t g^thcreth and converts all th,ngs to himfclf , wbuh are
de»tur, f/M mo- mozicd, illujlrated, Tfax hot^ attd (in a word) thoje ihmgs rpot
vem»r, ^-..uiu. preferred by Im fplendor : Wherefore the Sun k called^ f'
lefaint,&tino no- for that he colUSteth and gather eth together all things aijp^'j

JUS Jpltnclore Cin- rr 1 ^ i - jr j.1 fa thitl(^^

ti»emur, ita^'ie wefee^as touching the Ejjences and Onalities of thojeif^*o^^
SoiU^iQ-dicitfsr^ ^.fjf^lj fall <v<vithin our Senfe^ being 'very many and different r )
Irf^^Jc^//^^'^^^ if he 'who k one^ and equally bejicv^es his Light , doth reffj^l
Mifperfa. noHriJhy defend^ perfect^ divide j conj oyn^ cberijh ^ mak^ frHitj^* ^

Sol \2 Inemvl cncreafe, change^ jtx^ prodnce, wo^e^ and fajhton all Having cr(^'^
demtu, eorum<jii^ tHrc s : And e'z/ery thiHg h this Vniverfe at hi6 fleafure ^
ff f't'"". tahr df one andthe fame Sun h and the canfes of many thini^
^itaittates,qu4tq'ie TPtJfch participate oj him^ are equally aHticipatecl in bim : tcna^
mnh^fnt .c dtf- / / ^^^^^^ reafow, &c. The Sun therefore being the FoU^'

cfi.^q'ix' tain ot Light and, Principle or Motion, God intending ^ tn^^
urnqne Umen ^^ic Command of Jofhua^ all the Worlds Syftemc , fliould coi^
ht'l^^e^Hr^^^^ tinue many hours in the fame ftate, it fufficeth to make the Sa
Mvtdit,co?tjii»pt, ftand ftiU^upon whofeftay (all the other Convcrfions cealmg/
£4rt7.t Earth, the Moon,the Sun did abide in the fame Conftuut^

before as like wife all the other Planots : Nor in all that U
T-'&^^Z;, <li<itbc Day decline towards Night, but it was miraculoiiflypf^
ras hijus nmvir- longcii : And iiv this mannct^ upon the Handing ftill of chcbUj
ji[4tis , pre cav'.a ^yjchout altering, or in the leaft difturbing the other Afpefts^i^
ftifZTsoiV'lfl mutual Pofitions of the Stars, the Day might be Icngthned ^
fawceps, ca!i[jtf- £arth 5 which cxaftly agreeth with the Litteral fenfe of the S^^r^

qu^iparticip ifJt, in i CXC ^

fe ^qt4abiiu€- fim; that of which, if I be no|: miftakcn, we are to maiC'e
^^Jt^t foiall account, is, That by^help of this Ccf Hypothei||;
».r,&c. ' we have the Litteral, apert, and Natural Senfe of^anoth^r P^^,^
cular that we read of in the fame Miracle j which is^ That t
Sun flood ftill in Medio C^li : Upon which paflage grave Di^*^ ^
raife many qucftions, in regard it feemetk very probable, *
when Jojhuahdefircd the lengthning of the Day , the ^^j^^
nearil trtng,andnotin the Meridian j for if it had been i» ^ ^
Meridian , it being then about the Summer Soljlice, ^^^^ .^/^^y
fequcntly the dayes being at the longeft, it doth not feem h^^^^
that it was necelTary to pray for the lengthning of the day ?
profecutc Viflory in a Battail, the fpace cf feven hours and n^^^^^
which remained to Night, being fufficient for that P^^'P^^j,^
^tpon which Grave Divines have been induced to think that
Sun v^ras near fetting: And fo the words thcmfelves ^^^^^^j

Scltm fittift.

/mI-hilosophicaL Controversies. 459

found, faying, Ne mcvcaris Sot , jie mo<veark. For if it had
been in the Meridian, either it had been necdlefs to have asked
a Miracle, or it would have been fufRcicnt to have onely praid
for fome retardment. Of this opinion is Cajetan^ to which fub-
foibeth M-i^j^/iaHeJ, confirming it by faying, that Jojhua had
that very day done 16 many other things before his commanding
the Sun, as were not poflibly to be difpatch't in half a day.
Whereupon they are forced to read the Words in Medio Cali
(toconfefs the truth) wirh a little harflinefs, faying that they
••mp n-t no more than this : That the Sun jloacl ftill, being in our
^emifpherc that is, ahove the Hori%on. Bnt (if 1 do not erre) . , _
We fhill avoid that and all other, harfli expofitions, if according t^^lf^' Zf:', ,
to the Copermvin Syfteme we place the Suli in the midft, that frfrafdHctt Ho-
iVin the Centre of 'the Coeleftial Orbes, and of the Planetarjr
Converfions,- as it ismoft requifite to do. For Itippofftig any
'lour of the day (cither Noon, or any other, as you fliall pleafe
neercr to the Even ins) the Day was lengthened, and all the
Coeleftial Revolutions flayed by the Suns ftanding fti",/« the
that is,i« the Centre of Heaven, where it rcfides : A
Scnfe fo much the more accomodate to the Letter (behdes what
hath been faid already) in that, if the Text had defired to have
affirmed the Suns Reft to have been caufed at Noon-day, the
proper expreffion of it had been to fay, hpoodfliU atHoon-day,
ottnthcMcridianCircle, and not in the midft of Heaven: la
regard that thStrue and only Middle of a Spherical Body (as is
Heaven 3 is the Centre.

Again as to other places of Scripture, which feem contrary to
thispofition, I do not doubt but that if it were acknowledged
for True and Demonftrated thofc very Divines who fo long as
'hey rephte it falfe, hold thofe places incapable of Expofitions
that agree with it would finde fuch Interpretations for them, as
(hould very well fuit therewith i and efpeaally if to the know-
H.^ of Divine Learning they would but adde fome knowledge
of the Aftronomical Sciences : And as at prefent, whilft they
deem itfaUe they think they meet in Scripture only with (uch
places as makeagair.ft it, if they thall but once have entertained
another conceipt thereof, they would meet F"dventure as marjy
others thataccord with it, andhaply would ,udge, that the Holy
Church doth very appofuly teach, That God placed the Sun m
the Centre of Heaven, and that thereupon by revolving ,t m .t
felf, after the manner of a Wheel, He contributed the ordmary
Couries to the Moon and other Errat.ck Stars, whilfl that ftic

Sin

Coeli Veus fan^ijpme,
Qjti hcidum Centrum Poli.

M m m 3

Candore

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

Auikoriiy 0/ S c r i p t u a s

Candorefhigk ignco^
Augens decora tiimuiCj
Quarto die^ qui fldmmeam
Solk rotavi conflitucns
huna miniflrai ordinem^
Vagofque curfm Syderum.

They might fay, that the Name of Firmament very well a-
greeth, ad liter am, to the Starry Sphere , and to all that whic^
is above the Planetary Converfions , which according to ^^^^y^
pothefis is altogether ^rwtf and immoveable. Ad litteram
Earth moving circularly) they might underftand its folih
where it's faid, Ner dum Terramfecerat^ ^ finminay ^
' Or Poles. ^^^^ Terra, Which Car dines or * Hinges feem to be afcribc<*

to the Earth in vain, if it be not to turn upon them.

FINIS.

A N

B S T R A C T

OF THE

Learned Treatife

O F

JOHANNIS KEPLERUS,
The EmpQTOUts Ji'lathemticm:

EN TITULED

His Introdaclion ufon M A R S :

^^-r=r5^Ail T muft be confeffed , that there are very
^^H^.fsflil n»ai,y >^ho are devoted to Holineffe,
that diffcnt irom the Judgment of Co-
ftrmciisy fearing to give the Lye to the
Holy Ghoft Ipeakiag in the Scriptures,
if they (hould fay, that the Earth mo-
vcth,and the Sun ftandbftill- But let
fuch confider, that fince we )udge of ve-
«^^^^2^^==J rv many, and thole the moft principal
thingsby thcSenf of Seeing > is i.^^^^^^^^

; oT Ltr": tk a-'i^agto theSe„fe J
HS':tl "we'certainly k.K,w that the things ^^f^^:,
':. An Example whereof we have in that Verle oi

Fro'vchimnr fortn, Terr^qxe urbefiHC rcccdnnt.

So whenwecomeforthof the narrow ftraight 0^^-^^^
Wy,vvefayrhatalargeFieid<^^lco^^^^^^^^

^"er, Dhc in altmn ; [Lanch toith into '''^ ucep g j

»^if the Sea were higher than its Shores ; For lo « ^emeth to
%e but theOpticks (hew the caufe of th. fallacy Yet
Chrift'S'feth he -oft received Speech, although it proceed from
this delufion of the Eyes. Thus we concewe of the R^Gng and

^thcrwife

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

The (^Authority of S c a i p t u r

Setting of the Stars, that is to fay^ of their Afcenfion and D^^'
cenfion , when at the fame time that we affirm the Sun rifeth, o-
thcis fay, that it goeth down. See my Optices Aftr^nomict^caf-
lo.fol.^iy. So in like manner, the jP^^/i?w^/t/^/ affiti-m , that the
Planets flund Jiill^ when for fome dayes together they feeni to be
fixed, although they believe them at that very time to be moved
in a direfl: line , either downwards to , or upwards from the
Earth. Thus the Writers of all Nations ufe the word
WW, and yet they xienythajr. the Suii doth really ftand ftill. Lil^^'
wife there will ^i^er any man be fo deVoted to Copernirm^ but
he will fay, the Sun entereth into Cancer and Leo , although h^
granteth that the Earth enters C^/?r/V(?r« or Acj^narim : And
in other cafes of the like nature. But now the Sacred Scripruresj
fpcaking to men of vulgar matters (in which they were not i^'
tended to inftruft men) after the manner of men, that fo they
might be underftood by men, do ufe fuch Expreflions as
granted by all, thereby to infinuate other things more Myfterious
and Divine. What wonder is it then , if the Scripture (peaks
according to mans apprehenfion, at fuch time hen the Ttni^
of things doth diffent from the Conception that all men? whe-
ther Learned or Unlearned have of them } Who knows not
that it is a Poetical allufion^ PfaLip. where, whilft under the fi"
militude of the Sun, the Courfe of the Gofpel, as alfo the Per^^'
grination of our Lord Chrift in this World, undertaken for out
fak^s, is defcribed. The Suft is (dLid to come forth of his TaLer^^^'
cle of the Horizon ^ as a Bridegroom out of his Cha^jtbcr^
joycing as a Giant to rnn a Race ? Which Virgil thus imitates 7

Tithono crocenm Itnquens Aurora cubile :

For the firft Poets were amongft the Jews.The Pfalmifi: knew that

the Sun went not forth of the Horizon, as out of its Tabernacle,

& yet it feemeth to the Eye fo to do: Nor did he believe,that the

Sun moved, for that it appeared to his fight fo to do. And yet h^

faith both, for that both werefo to his Teeming. Neither is

to be adjudged falfe in either Senfe: for the perception of tb^

Eyes hath its verity, fit for the more fecret purpofe of the Pftl'

mift in fliadowing forth the current paffage of the Gofpel ,

alfo the Peregrination of the Son of God. Jofhna ]ikev\'ii^

mentioneth the Vallies on or in, which the Sun and Moon i^^'

ved, for that they appeared to him at Jordan fo to do ; An^l

both thefe Pen-men may obtain their ends. Da^zd^ (and with

him Syracides) the magnificence of God being madcknown?

which caufed thefe things to be in this manner rcprefentcd to

Of ocherwife,- the myftical meaning, by means of thefe

Vifibles being difcerned: And ya/7;«^^ in ihat theSun, as to hn

Senic

/» P H I L O S O P H 1 C A L <^ P M T R .0 V E R S I E S,

Senfe of Seeing, ftaid a whole day in the midft of Heaven,wheic-
»s at tin: fame cime to others it lay hid under ihc Earth. But in-
<:ogitant perfons onely look upon the contrariety of the words,
^I'cSHnjioodftdl, that is,T/jf Earth flood ftilli not conlidenng
thattliiscontradiaionis confined within the limits of the Op-
ticks and Aftronomy : For which caufe it is not outwardly ex-
Ned to the notice andufeof men: Nor will they underftand
that the onely thing Jopjuah prayed for, was that the Mountains
■night not intercept the Sun from him ; which requeft he cxpref-
fed in words, that fuited with his Ocular Senfe : Bel.desu had
been very unfeafonable at that time to think of Altronomy or
theErrours in Sight ; for if any one fliould have told him that
'he Sun could not really move upon the Valley o£ Ajalon, , but
onely in relation to Senfe, would not Jopnah have rcplyed,that
^is defire was that the day might be prolonged, (o it were by
«ny means whatfoever ? ' In like manner would he have anlwercd
'f any one had ftarted a queftion about the Suns Mobility , and
t'le Earths Motion. But God eafily underftood by
^vords what he asked for, and by arrefting the Earths Motion,
madetheSuninhisapprehenfion feem to ftand AiU. For the
ia^monofhitabs Prayer amounts to no more but this, that it
mijihtthusappeartohim, letitinthe mean UOic be «>hut tt
^owWofitfelf. For that its fo feeming, was not in vam and
ridiculous, but accompanied with the defired eifca. But read
the tenth C/^a^^. of my Book, that treats of the Optickpirt of A-
hommy, wHere thou (halt findc the Rcafons why the Sun doth
'li this manner feem to all mens thinking to be moved, and not

the Earth i

as namely, becaufe the Sun appeareth fmall, an tie
£ai th bigg. Again, the Motion of the Sun is not difcerned by
theeyc byreafon of his feeming tardity , but by ratiocina-
tion onely - in that after fome time it varieth not «f Pr™.ty m
'uch and fuch Mountains. Therefore it is impofliblc that Rea-
son, unt " t Te firft inftruaed, (hould frame to it fe f any other
apprehenfion, than that the Earth with Heavens Arch placed
t>ver it, is as i were a great Houfe,in which, being immoveable,
the Sun Uke a Bird fly ing in the Air, pafTeth in fo Imall a Spec.es
outofone Climate iiuo another. Which ,maginatio.i of all
^an-kinde being thus, gave the firftUne in the Sa«cd Reaves :

, fo,^hat thefe two are moft obvious to the eye^ As if
V- niould have laid thus to Man -, This whole Mundai^ Fa-
"^tid which thoufeeft, lucid above, and dark and of a vaft ex-
^^"t beneath, wherein thou haft thy being, and with which thou
irt covered, was created by God.

In anodier place Man is queftionedi Whether he can findc out^

464 The (^utbority of S c]r 1 1> t u r

the height of Heaven abo'Zfe , or depth of the Earth beneath : for
that each of them appcareth to men of ordinary capacity, to have
equally an infinite extent. And yet no man that is in his right
mind will by thclc words circumfcribe and bound the diligence
of Aftronomcrs^whcther in demonftrating the moft contemptible
Minuity of the Earth, in comparifon of Heaven , or in fcarching
out Aftronomical Diftances : Since thofe words fpeak not of the
Rational, but real Dimention ^ which to a Humane Body?
whilft confin'd to the Earth, and breathing in the open Air, is al-
together impoflible. Read the whole 38. Chapter of Job , ana
compare it with thofe Points which are difputcd in h.i\\' onoi^'i •>
24- 2. and Phyfiologie. If any one do alledge from Pfali^, That * T/^^
Earth %j founded upon the Seas^ to the end that he may thcn^^
infer iomc new Principle in Philofophy, abfurd to hear j as, Th^^
the Earth doth float upon the Waters , may it not truly be toW
him. That he ought not to meddle with the Holy Spirit , noi tc>
bring him with contempt into the School of Phyfiologie*
For the Pfalmift in that place means nothing ellc but
that which men fore-know, and daily fee by experience ^ namely?
That the Earth ("being lifted up after the feparation of the
ters) dothfwim between the Grand Oceans, and float about the
Sea. Nor is it ftrange that the expreflion fliould be the lani^
where the Ifraelites fing, * Tihat they fate on the Ri^yer of 3ab)'
Kal.137.1. Ion \ that is, by the River fide, or on the Banks of Euphrates an^

If any one receive this Reading without fc ruplc, why not the

other j that fo in thofe fame Texts which are wont to be alledg^^

agaiiift the Motion of the Earth, we may in like manner turn ou^

eyes from Natural Philofophy, to the fcope and intent of Sen*

pture. One Generation paffeth arvay^ f faith Ecclefiafles) and A'

'Chap.i.v,4,to not her Generation cometh: But the Earth abidcth for ever, * As

9' if Si;/oW(;» did here difpute with Aftronomers, and not rather put

men in minde of their Mutability \ whenas the Earth, Mankindc^

habitation, doth alwaics remain the fame : The* Suns Motio^^

doth continually return into what it was at firft : The Wind 1^

aftcd in a Circle, and returns in the fame manner : The Rivef^'

flow from their Fountains into the Sea , and return ag^in troi^^

thence unto their Fountains : To conclude. The Men of

Age dyingyOthers are born in their room ^ the Fable of L^^-'

ever the fame \ there is nothing new under the Sun. Here

reference to any Phyfical Opinion, ^ •l>3lff/ais Moral of a thing ^{V!*"

felf manifcft, and feen by the eyes of all, but little regarded: A

that therefore which Sf?fo;//f?/^ doth inculcate. For who knoWS i>^^

that the Earth isalwaies the fame ? Who fees not that the Sun

dothariCefiom the Eaft ^ That the Rivers continually run 'i^^^^

the

Ph I L OSOPHlC AL G OMT^R O Vfi RSIE S. ^6^

^fic Sea 5 That the viciflkudcs of the Winces return into thcir
primitivc State ^ That fome men fiicceed others ? But who con-
fidercrththat the felf-fame Scene of Life is ever afiiitg, by diffe-
rent perfons j and that nothing is new in humane affairs ? There-
fore Solomon inftancing in thofe things which all men fee, doth
piit men in minde of that which many thorowly know, but too
%htly confider.

But the 104. Ffalm is thought by foiile to contain a Difcourfe
altogether Phyfical, in regard it onely concerns Natural Philofo-
pl^y- Now God is there faid. To have laid the F oitndations of Pral.104. v 5.
^^e Earthy that it fhonld not be removed for evsr. But here al-
fo the Pfalmift is far from the Speculation of Phyfical Caufes :
f^or he doth wholly acquiefce in the Greatneffc of God,
^ho did all thefe things , and fings an. Hymne to God the
Maker of them, in which he runneth over the World in order,
it appeared to his eyes. And if you well confider this
^falme, it is a Paraphrafe upon the fixdayes work of the Crea-
^jon : For as in ic the three firft dayes were fpcnt in the Separa-
tion of Regions 5 the firft of Light from the cxtcriour Dark-
; %\ic fccond, of the Waters from the Waters, by the inter.
Pofition of the Firm ament , the third^ of the Sea from Land ;
^hen alfo the Earth was cloathed with Herbage and Plants:
And the three laft daycs were fpent in the filling the Re.-
gions thus diftinguifhcd ^ the fourth , of Heaven ^ the
^fth 5 of the Seas and Aire 3 the fixth , of the Earth :
W in this Pfalme there are fo many diftinft parts prd-
jportionable to the Analogy of the fix dayes Works. For
in Verje 2. he cloatbs. and covereth the Creator with Light
(^he firft of Creatures, and work of the firft day) as with a
Garment. The fecond part beginneth at Verfe 5. and treats of
^te Waters above the Heavens, the extent of Heaven and of Me-
[eors (which the Pfalmift feemeth to intend by the Waters a-
^^ve) as namely of Clouds, Winds, Whirl- winds, •Lightnings,
^hc third part begins at Verfe 6. and doth celebrate the Earth
the foundation of all thofe things which he here confidereth.
f'or he referrcth all things to the Earth, and to thofe Animals
^l^ich inhabit it, for that in the judgment of Sight the two prin=
^^Pal parts of the World are Heaven and Earth. He therefore
h^rc obferveth that the Earth after fo many Ages hath not falte^
^^d, tired, or decayed ; when as notwitbftanding no man hath
difcovcred upon what it is founded. $ He goeth not about to
^J^^ men what they do not know, but putteth them in minde
r ^vhat they negleft, to wit, the Greatneffe and Power of God
treating fo huge a Mafs fo firm and ftedfaft. If an Aftrono-
fliould teach that the Earth is placed among the Phnets, he
N n n

#ver-

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2°K.B. 9,163

Tie Atitboriiy 0/ S g r i p t ii n s

overthrovveth not what the Pfalmift here faith, nor doth he con-
tradift Common 'Experience j for it is true notwithftanding?
that the Earth, the Strufture of God its Architeft, doth n^t de-
cay (as our Buildings are wont to doj by age, or confun^^
wormes, nor fway and leane to this or that fide , that the Seats
and Nefts of Living Creatures are not molefted j that the
Mountains and Shores ftand immoveable againft the viol'^nceo
the Winds and Waves, as they were at the beginning. Buttne
Pfalmift addeth amoft Elegant Hy pot hefis of the Separation oi
the Waters from the Continent or Main-land, and adorns
with the produSien of Fountains, and the benefits that Springs
and Rocks exhibit to Birds and Beafts. Nor doth he omit the
apparelling the Earths Surface, mentioned by Mojes amongft
works of the third Day, but more fublimely defcribeth it in
Cafe in expreflions infufcd from Divine Infpiration j and floU^^'
fheth out the commemoration of the many commodities whic**
redound from that Exornation for the Nourifliment and CoU^'
^ Shdcc^ . fort of Man, and" Covert of Beafts. The fourth pare begins
at Verfe 20, celebrating the fourth dayes work , "z/i^. X^e Sii^
and Moon , but chiefly the commodioufneflc of thofe things*
which in their Scafons befall to all Living Creatures and to M^"'^
this being the fubjeci matter of his Difcourfe : So that it P.
ly appeareth he afted not the part of an Aftronomer. For u
had, he would not then have omitted to mention the five Planef^J
than vvhofe moitoa nothing is more admirable, nothing moree^'
cellent, nothing that can more evidently fet forth the Wifd^^^
of the Creator amongft the Learned. The fiftli part bcgi[^^»
Vcrfe 25. with the fifth Dayes work. And it ftores the Seas v^^J*'
Fi{hes> and covers them with Ships. The fixth part is more ou'
fcurely hinted at, Vcrfe 28. and alludeth to the Land-C features
that were created the ifixth day. And laftly , he declareth the
goodnefie of God in general, who daily creatcth and preleive
all things? fo that whatever he faid of the World is in relatio^
to Living Creatures ^ He fpeaks of nothing but what is grante
on all hands ^ for ihat it was his intent to extol things know^ '
and not to dive into hidden matters, but to invite men to eo^^
template the Benefits that redound unto them from the works
each of thefe dayes. . .^^

And I doalfo befeech my Reader, not forgetting the
GoodnefTe conferred on Mankind ', the conlideration of^

Creator/which 1 difcover to him by a more narrow ^^P'^^^^|^^
of the Worlds Form, the Difquifition of Caufcs, and P^t^ j

P H f L O S O PB 1 C A L C O N T R O V £ R S I E S.
^ the Errours of Sight : And fo he will not oncly cxtoll the
^ouiuy Of God in tiic prefervation of Living Creatures of all
^"}des, and cftablifliiHent of the Earth , but eVcn in its Motion
which is foftrange, fo admirable, he will ackn6\vkdge the
Wildome of the Creator. But he who is fo ftupid as not to
^'ouiprehend the Science of Aftronomy^ or fo weak and fcrupu-
^^us as to think it an offence of Piety to adhere to CopernicpfSy
"»mladvife,that leaving the Study of Afironomy^ and ccnfuring
«c opinions of Philolophers at pleafure, he betake hinnifelf to
nis Own concerns, and that defifting from further purfuit of thefe
^"tricate Studies, he keep at home and manure his own Grouiid ^
with thofe Eyes wherewith alone he feeth , being eleva-
towards this to be admired Heaven,' let him pour forth his
Jj'nole heart in thanks and praifes to God the Creator j and af-
j ^**e hinifelf that he fliall therein perform as much Worfliip t6
OQj as the Aftronomer^ on whom God hath beftowed this Gift,
though he feeth more clearly with the Eye of his Under-
^nding j yet whatever he hath attained to, he is both able and
^^iling to extoll his God above it.

And thus much concerning the Authority 6f Sacred Scripture.
^'^W as touching the opinions of the Saints about thefe Natural
'^^ints. I anfwer in one word, That in Theology the weight of
^uthority, but in Philofophy the weight of Reafon is to be con-
^dered. Therefore Sacred was La6lantius ^ who denycd the
^^rths rotundity Sacred wis AugHfiine, who granted the Earth
J^W round, but denyed the Antipodes-, Sacred is the ^Liturgy of * O&cmta
Moderns, who admit the fmallneffe of the Earth, but deny
Motion : But to me more facred than all thefe is Truth, who
fro Doftors of the Church, do demonftratc

^ ^ Philofophy that the Earth is both round, circumhabited by
^^^P^des^ of a moft contemptible fmalneffc, and in a word,
it is ranked amongft the Planets,

Nnn a

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2°K.B. 9,163

ABSTRACT

Some paffages in the Commentaries of

Didacus k Stunica,

O F

SALAMANCA

Upon JOB:

The Toledo Edition, Printed by 7 0 H N R 0 P E R K
Anno I « 84, in Qnarto , Pag. 205. & feqi- 00
ihefe Words, Chap. 9. Vctle 6-

JVhojhahth the Earth out of her place, and the Vil-
lars thereofTrmbk

^e'-SacreS Pen-man here fets dow;i .anothqr;^^'
fed whereby God flieweth hi^ i^^^^P^^^l^
Wer, ioyned with infinite Wif^pm-
place, though it muft be confeffed very diW
cult tounderftand, might be greatly clearc
by the Opinion of the Fythagonans , v

.. hold the Earth to be moved of its own En^^

ture/and that the Motion of die Stars can no other way be ale
tained, they being fo extreamly different in t-dity a„d ve oc. )

Srwhichludgem^ntwasF/././.^^ and H--/'^- ^-'^^'h;
rimarch relateth in his Book Dc Flacitis Fhtlofof^ornm : v
were followed by ^ma FewpiM^^s , and, which 1 more r ^^^at
The Divine P/.J. in his old age ^ ir^lomuch that he ^^'^ ..S^
. n , r J u:„i, -^rherwife. as the fame Vlutard^

itwasmoftabfurd tothink otherwife, as the fame
us in his ^ mm^. And Hypocratesjn his Book De i" . -

calleththe Air"0«'XV'''i- ''•The Earths Chariot.

But in

this
ouf

net

bui

G
h
b

tl
\
il

£
t
1

HI L OSOPHIC AL

NTROVERSIES.

<>^t hgc^CopernicHS doth demonftratc the courfes of the Pla-
nets to be according to this Opinion. Nor is it to be doubted
but that the Planets Places may be more exaftly and certainly
^fllgnedby hisDoftrine^than ftolomies Great Almogeft or
Syfteine, or the Opinions of any others. For its manifeft , that
Ototomy could never defcribe either the Motion oftheEqui-
Jioxes, or aflign the certain and pofitive beginning of the ¥caf :
the which he ingeniouay confeflbth in Lib. 3. De Almagefi. Mag-
^^m. Ch. 2 . and which he leaveth to be difcovered in after times
'^y thofe Aftronomers, who coming into the World much later
Aan he, might be able to invent fome way to make more accurate
obfervations.And although the * Alphonfiues ScThdith Ben Core
have attempted to explain them j yet it appeareth that they have
<lone as much as nothing. For the Pofitionsof the ^/^^^^^^/yz/^^i-
<lifagree amongft themfelves, as Kicim proveth. And although
Ae Reafon oithebith be more acute , and that thereby he de-
termined the certain beginning of the year , (being that which
fought for) yet it is now clear, that the Progreflions of
^he Equinoxes are much longer than he conceived they could be.
.Moreover, the Sun is found to be much nearer to us than it was
held to be in times paft, by above fourty thoufand ! Stadia, or
furlongs. The Caufe and Reafon of whofe Motion , neither
holo^ nor any other Aftrologers could ever comprehend : And
yet the Reafons of thefe things are moft plainly explained and
^cmonftratcd by Copernicus (torn the Motion of the Earth, with
^Uch he flicweth that all the other VhMomena of the Univerfe
^0 more aptly accord. Which opinion of his is not in the leaft
contradifted by what 5(?/<j;^i^» faith in * Ecclefiaftes : Bnt the
'^arth abideth forever. For that Text fignifieth no more but
this, That although the fucceffion of Ages, and generations of
Men oh Earth, be various h yet the Earth it felf is ftill one and
*e fame, and continuqth without any fenfible alteration , For
the words run thus : One Generation pa ffeth dw ay, and another
^^neration cometh but the Earth abideth for ever. So that it
hith no coherence with its Context , (as Fhilofophcrs tliew) it it
^^expoundedto fpeak of the Earths immobility. And al-
^•^ouahin this Chapter Ecclefiaftes, aiid in many others Holy
Writafcribes Motion to the Sun, ^sVxzhCopernicm will have to
ft^nd fixed in the Centre of the Univerfe •, yet it makes nothmg
^gainft his Pofition. For the Motion that belongs to the Earth,
I? by way of fpecch aQlgnedto the Sun, even by Copernicus him-
'^If. and thofe who are his followers, fo that the Revolution of
Earth is often by them phrafed, The Revolution of the Sun.
To conclude, Noplace can be produced out of Holy Scripture,
^hieh fo clearly fpeaks the Earths Immobility, as this doth its

* Followers of
that Learned
Kings Hypochc-
fis.

That I's 5000
Jnilcs ; eight of
thcfc making an
fta/iaMyOi: Sr^hf^j
mile ot a 1000.
paccs.cvery pace
containing 5.
Fecr.

KChap.i. V.4.

The Motion of
the Earth, not a-
gainft ScripturCo

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2°K.B. 9,163

The Authority 0/ Scripture

Mobility. Therefore this Text, of which we have fpoken, isei*
fily reconciled to this Opinion. And tofet forth the Wonder-
ful power and Wifdome of God, who can indue and a flu ate the
Frame of the Whole Earth (it being ot a nionftrous weight by
Nature) with Motion, this our Divine pen-man addcth ?
the pillars thereof tremble : As if he would teach us, from the
Do&rinc laid down, that it is moved from its Foundations.

A N

E P I S

I
I

of the Reverend Father

^AOLO ^NTONIO F0SGA1{l5^h

A CARMELITE ;

Concerning

The P rTH^GORI^N and COf£RN/CyiN Opinion

O F

The Mobility of the £ ^ R r H,

AND

Stability of the S V 1<1

AND

Of the New Syfteme or Conftitution
OF THE

WORLD.

IN WHICH,

The A uthorities oiS ACRED SCRIPT qjRs^
sind ASSERT lOHS of DIVINsS,

commonly alledged againft this Opinion^'
are Reconciled.

W R1TTE.N

To the moft Reverend F a T h E

SEBASTIANO FANTONI.

General of the Order of Carmelites.

V.nglip}ed front the Original^
THOMAS S ALVSBV^IE.

SotfHts indifet f^pemta^ fofttttet

a T)c9, J^cobi T. vcrfu.
OptAvi, & datui efi mth* [<n[Mt.
' Sa^iencig 7- vcrfu. 7.

Piintedby WILLI AM LEY BOV RNi MDCLXI.

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2°K.B. 9,163

473

To the

Reverend Father

BASTiANO

F A K T O N i

General of the Order

CARMELITES

N dbedieiice to the Command oiF, the No-
ble SigndreVincen'i.o Carrafa^^t^e^po'
Utan, and Knight of S: John of Jem.
Calm, (aperfdri, tdfpeak the truths of
fo great Merit, that in hVm Ndbihty of
Birth, Affability of Manners , Univerfal
knowledge of Arts and things , Piety
and Vettue do all contend for preHcmi-
^^...-,...„^^.^-.^ ilence) I refolved with ihy felf to un-

Subilny of the ^''"y^'^'l'-l^^i,. CoPcrnit^s^ who W
S""**, and at laft reduced ^ svftehie And Conftitutioii

We hath deduced the J ^^^^^ : on which

Of the World and its ^['^/^^"^^^^^ftXerend Sir : But
Subjeai have formerly writ to ^ ^ , Coni^

'n regard 1 ambbund for Kcme P^f^'^^^^^^^^ for
^^Js and fince this Speculation may^^^^^^ ^

mother Trcatife, to w.t , a "^^^^^^'^^^^^^^ that it may

"> hand with, »^^^^''^\'Z c'Zyi«r»ofthe.Lib^^^^

^omeforth in company ^^"^f i^Cnov^^ dlfcufs it by if
^v kh I have, already fim(hed,iatol«n n^^^^ ^^^^ .

f^lf, I thought to fo.bcar, ^"^X mean time, abrief ac
P^efcH ; Vcc I was def.rous to give, m ^^^^^
^ouiuof thismyqctermnutuin a^>d and my very

^;nd Father, Cto -^-- I 7^;^^^^^^^^^^^ grounded!
l^aftl -m otherwife it is favoured with much frobabihty ir^^^^^
found inreaiicy to be cxtreamly^epu|nant (a» at firft figh^t

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2°K.B. 9,163

The Authority o/Sgripture

feems) not onely to Phyfical Rcafons, and Common Principle^
received on all hands (which cannot do lo much hajm) but aji
(which wouldbeof far woifecbnfequence) to many Authon
ties of facred Scripture Upon which account many at ttiei
firft looking inlo-itrCXpYode itK^h^ ^^^^ (o^id Paradox an
Monftrous Capriccio that ever vva» heard of. Which thing P^-^
ceeds only from an antiquated and long confirmed Ciiltomj>
which hath fo hardened men in, and habituated them to Vu
aar Plauiible, and for that caufe by all men (afwell learned
unlearned) Approved Opinions, that they cannot be remove
one ftep from them : So great is the force of Cuftome (wmc
not unfitly is ftileda fecond Nature) prevailing over the whol^
World, that touching things men are rather pleafed vi^ith,
lighted in, and defirous of thofe, which, though evil and obnox-
ious, are by ufc made familiar to them, than fuch, wherevvK"?
though better, they are not accuftomed and acquainted. So
like manner, and that chiefly, in Opinions, which when oncetW
are rooted in the Mind, men ftart at, and rejeft all other
whatfoever *, not only thofe that arc contrary to, but even ai
that ever fo little dilagrec with or vary from theirs, as harm t
the Ear, difcoloured tp the Eye, unplcafantto the Smell, nam^^
ous to the Taft, rough to the Touch. And no wonder :
Phyfical Truths arc ordinarily )udgcd and eonfidered by ti^^^j
notaccordrng to th^ir Effence, but according to the prefcnpt
fome one whofe detcription or definition oF them gaines hii?
Autho^ty amongft the vulgar. Which authority nevertheki^
(fince/tk-po, more than humane) ought not to be fo efteemcd, a$
tha^ that. which doth manifeftly appear to the contrary, whethej
from hqtf^r Reafons lately found out, or from Senfe it fclfiflioula
%j«*i&ke be contqn>ned and flighted j Nor is Pofterity fo to W
^lopfipqdj butthatit m not only proceed farther

^)ut alfo bfiaig to lig^ bett^^ Experiments than thoi^

w^cbb:^ye been delivered to us by the Ancients. For the 0^'^
nine's otxht Antient?, as in Inventions they did not much ft^'^'
pafs the VVits of our times •, fo for the perfefiing of Inventio^^^
this Age pf ours feems not only to equal, but far to cxcell format
Ages j Knowledge, whether in the Liberal or Mechanical ^^^^
daily growing to a greater height. Which AfTcrtion mig^c ^
cafily proved, were it not that in fo clear a cafe, there would ^
more danger of obfcuring, than hopes of illuftratingic with any
farther light. ,
But(that I may not wholly be filent in this point)have not tn
fevcral Experiments of Moderns, in many things, flopped tn^^
mouth of Venerable Antiquity, and proved many of their great-
teft and weightieft Opinions, tp be vain and falfe? The DoCtnn

H r t

OSOPHICAL CONT ROVERSIEs;

475

the
aC'
\0C

of the Antipodes by many of the Antieiits of approved Wif-
•lome and Learning was held a Paradox no leG ablurd than this
Our Opinion of the Earths Motion may reem to be i as likewife
'hat of the Habitableiiejfe of the Torrid Zone : Of thefe Opini-
ons, thefiift was accounted unpofllble by many, but tlie latter
'vasabfolucely dcnycd by the unanimous coulent of all : But
'»ter Authors (to tlie grea: felicity and perpetual Glory of
their Age J) have, not fo much by Authority, as by accurate
•^'ligenA: and indefatigable ftudy to finde out the truth , p o-
ved them both to be^'uadoubtedly true. Thus 1 ailinn that
'he Antients were deceived, and that in too lightly challenging
Credid and Authority for their Inventions, they dilcovered too
"luch folly. Here for brevities fake I pafs by many Dreams
Wly detcfted, both of ArjjlotU and other of the antieut Philo-
%hers ; who in all likelihood if they had dived into the Obfer-
^itions Of Modern Writers, and underftood their Pvcalons, would,
V charK'i .g their Judgements, have given them the precedency,
»nd would have fublcribed to their manifeft Truth. Hereby we
fee t!uc we are not to have fo high a refpefi for the AntieiiS , that
Whatever they aiiert ihojld be taken upon truft,a:.d inattaitU
fi-ould be ^iven to their fayings , as if they were Oracles and
Truths fent down from Heaven. But yet (which indeed is
«Wtly to be regarded in thefe mactets) if aiiy thing be found out
Ait is rcpvi:mant to Divine Authority, or to tiie Sacred Leaves,
that were diltatcd by the Holy Ghoft , and by His liifpiration
expounded by the Holy Doftors of the Church, in this calc not ^
°nely Humane Rcafon, but even Scnfe it lelf is to lubmut : .^J?.^
^l«ch, thou ni by all manner of weighty Condicions and oircum- /«.
fiances it ni;>uld hold fortli any thing contrary to Divme Autho-
rity, (which indeed is fo pbia, that there is no way letc to evade
tl>er,\l,cu„ eritandingof it)yct u it to be jcjefted^ and we
•nuftL.cludeourfclve.deceivedby it, and believe that thatis
not true which Scnfe and lleafou reprelents unto us:For,howcver
^ejud.eoft!Mnas,vvehave,bothin this and all other ca es, a
tnore certain knowledge, which proceeds from J^'J'"- F"'';'; '
S. fet.r hach moft eKcellently expreft U : Who though with h.
Wes he law, and perceived the Glory of our Lord ,n his
Ttan^nguration, and heard his words manifeftingh.s great Pow-
Jt^yec neverthelefsall thefe things compared J'^h/^e Light of
t^4,he adds : HVe ha<vc Jfo a more fnrc r.ord of ?ro{>hecy,Scc
^Vhelefore fince this Opinion o{?ythagor^ and Coperntcus hath
^ntred upon the Stage of the World in to ftrange a Drefs, and at
the tirft appearance (bef.des the reft; doth leem tooppole fun-
Authorities of Sacred Scripture, it hath (this being granted)
^een juftly reieaed of all men as a meet abfurdity.

O o o a

certain^ tha

n 2 Pet. I. 19'

Mobile.

The ^Htbority 0/ S c r. i p t u r e,

Bu' yet bccaufc the common Syftcme of the World Jevifcd by
f/6'/6»/)f hath hitherto Satisfied none of (he Learned, hereupon a
fulpi.ionisritcnupamongftall ^tven Ptolemy's followers them-
felves, that there muft be feme other Syfteme, which is more true
than this of Ff(7/cw)fj For although the Vb.itnomena of Ceki"^
Bbdys may fecm to be generally refolved by this Hypothefisj}'^'^
they are found to be involved with many difficulties, and retcr
red to many devices , as namely, of Orbes of fundry i orms
Figures, Epicicles, Equations,Differcnces,Exccrtritks, arClinJ^|^'
merable fuch like fancies and Chymxra's which favour of
I fjf Kationis of Logicians, rather than of any Kealem Effevt^f^^'
Of which kinde is that of the Kapd Motion^ than which I fi^' ,
not any thing that can be more weakly grounded,and more ca|i'
]y controverted and difproved : And fuch is that conceit of ^'^^
Heaven void of Stars, moving the inferior Heavens or Orbes •
All which arc introduced upon occafion of the variety of t'^^
Motions of Celeftial Bodyes, which feemed impoflible , by ^^"^
other way, robe reduced to any certain and determinate H^*'^'
So that the Affertors of that common Opinion , freely coi"^*''
that in defer ibing the Worlds S) ftemc, they cannot as yet
ver, or teach the true Hypothecs thereof: But that their cn^^^
vours are orcly to finde out , amongft many things , what is ii^^ ^
agreeable wich truth, and may, upon better and more accoitio
date Hcarons, ai.fwcr the Celtftiai Vhdnometta, .

Since that, the Tclcfcopc(anOptick Invention) hath been {o^^^
our, by lielp of which , many remarkable things in the Hcav<^f^^;
inoft worthy to be known, and till then Unthought of, were dii"
covered by manifeft fenfacion as for inftance, That the Moon
Mountainous ^ Venus and ^atuni Tricorporeal j and Juftn'i
•Quadri corporeal : Like wife that in xh^Via L^Se^, in the ilc
i/iriexjand in the Stars called Nohulof^e there are many Stars , an
thofe of the greateft Magnitude which are by turns adjacent
one another 5 and in theendithath difcovered to us, new fi^cc
Stars, new planers, and new Worlds. And by this fame Inlin '
ment it appears very probable, that Venus and Mercury do
move properly about the Earth, but rather about the Snn *,
that the Moon alone moveth about the Earth. What therei^^^
can be inferred from hence, but that the Sun doth ftand '^^.^t"
vablein the Centre, and that the Earth, with the other CeU^
Orbes, is circumvolved about it ? Wherefore by this and n^^^^y
other Reaions it appears, That the Opinion of Fythagoras an^
Copernicus doth not difagree with Aftronomical and Cofmogra-
phical Principles ^ yea, that it carryeth with it a great likehh^^
and probability of Fruth : Whereas amongft the fo many l^ve-
ral Opinions, that deviate from the common Syfteme , and deviic

others,

In Ph itosoph ical Controversies.

Others, fiich as wcic

' rhofe of

then

CarddttHS^Fracadorin

^11

Caf.

enc and Modern, there h not one found that .s mo;e taa.e, mo>e
regularly ahd determiaatcly , accommodatea to the Vb^nomcna
M Mocious of the Heavens, without Efuychs tx«»/rj, ho-
mccmrnkf Dcfercnts,andthc lupputation of the Rap.d Mot.on-
Aad this Hypothcfi. hath been alferted for true, not onely by
P>r/;.,...,,and> after him, by Copernicus, but by many famous
men. aVnamcly HeracUtus, and Ecpbamus^yhagoreans,^^\ the
Difciplcs of that Sea, Mketa oiSyracnfe Uaruams CapelU,zud
many more. Amongftvvhom, thofe (as we have faidj) that
have^atlmpted the imd.ng out of New Syftemes (for they t^fu-
fed botL th?s of ?ythagoJ, and that of Frolc'ny) J^e numberiefs:
who yet notwichftanding allowed this Opm.onof Pythagoras to
carry with it much probabil,ty,and indireaiy confirmed it ; inaf-
much as that they rejeded the common one as 'mperfea , defe-
aive ann teudcd with many contradia.ons and d.fEcult.es.
A n? rMnlV may be numbered Father * C/4^i«/, a moft learn-

refutes the Syfteme of ?ythagor.,
yet a knowlcdgeth the Levity of the common Syfteme , and he
nlnVoufly confe(reth,that for the removal ot ditf.cult.es,,n which
ttfclmonSvfteme will not ferve the turn, Aftronomers are
Weed to enquire after another Syfteme , to the dilcovery of
which, he doth very earncfily exhort them. „ . ^

Nowcaa there a better or more commodious Hypothefu
be deviled, than this of C<far«ir«.,? ForthisCaule ^nany Mo-
dern Authos are induced to approve of and follow .t . but
with much h=.luaacy, and fear, in regard that .t Jeemeth in the.r
nmucii n-Ki Scriptur-cs,as that it cannot

Opimonlo tocont ad.a ^' f "^^'^^ Jj, is the Reafon that this
P^lUUly be [econc. ledto hem ^h f ^ ^^.^^^

^ -Ued Face . acceding

that advice of the Poet :

jHdichm popnli mnqnam contempferis unus,
iie nulUs places, dum 'vis conumnere mltos.

Upo; confideration of which, (out of my very g-Jt love ^c.

^a^s the Sciences, ^^^^^T^^^:^^^-
P^rfeaioiiorthcm, and ttie ui rplf tou chintz

;ours and Obfcuaties)! began to a^g^ wK^^ ielf t^^^^^^^^

fl»s Point after this manner : This Opinion ot J ,
either true or falfe If falfe, it ought not to be mentioned, and
uhertruc,oriaiie,i ' it matters not, though it

Qcierves nottobedivulgto • ? '/n a a u ..<rh

contradia all, as well Ph.lolophers as Aftronomers : And though
foritscftablinimcnt and reducement to ufe a. new P^olopny

* P, Clavi.is in
lilciiiia fuor. Ope-
tumcduione^

The

jS The Authority 0/ S g r i p t u-r s

and Afti onoiny^Cfoiindcd upon new Principles and Hyporhcfc)
flioiild be coiilHtutcd : tor ihe Autboiity of Sacred Scripture
willrotoppofe 1 3 neither doth one Truth contradift another.
If theicfore the Opinion of ?ythagoras be true, without doubt
God hath difpolcd and diftatcd the words of of Holy Writ in
fuch a manner, that they may admit an apt fenfe and rccoucilia-
tion with that Hypothecs. Bein^ moved by theie Rcaious , and
the probability of the faid Opinion, I thought good to cry w'hc*
ther Texts of Sacred Scripture might be expounded accoiduig
Theological and Phyficai Principles, and might be recoiicikd ^o
it, fo that (in regard that hitherto it hath been held probable)
may in afccr limes, coining without fcruple ro be acknowledge'^
for true, advance it felf, and appear in publick with an uncover-
ed Face, without any mans prohibition, and may lawfully aii^
freely hold a ^acred intcl-igence with Holy Truth , io earncAly
coveted and commended by good Men. Which dei)gne3havinghi-
j4uthot thcito been undertaken by none that I know,wil,l am perlWadcd,
be very acceptable to the Studious pf thef^ Learning?,el'pecia]i> to
lartks o^htH- the moft Learned G^2//7.f<7 Galilxi^ chief Mathematician to the
Z^.^^IuC'^ ^/ moft Serene Grand Duke of rw/r^/zj^, and ^(^/jw Kcp/er, chid
^^crnsl ' ^' Mathematician to his Sacred arid invincible Maj^fty, the Emp^'
rour, and to all that Uluftt ious, and much to be commer.dcd Ac*
cadcmy of the Lj/«<:e7«/ j whom, if I miftake nor, aie all of ^^^^
i'^pinioa Although [ doubt not but they, and many other
Learned Men n.ighc eallly have found out thefe or the like R^'
conciliacions of Scriptural exprcfuonb ^ to whom neverihclels i
have thought tit (in refpcfi: of that profcffion w^hich I have imdei'
taken? upon the faith of my foul, and the propenfity that I have
towards Truth) to otfcr that of the Poet,

NhIUhs addiBm jurare in 'verba Magijiri.

And in teftimony of my cftecm to them and all the Learned,
to communicate thcle my thoughts ^ confidently affuiii g m)' 1<^'^
that they will accept ihtm, withk Candor equal to that where-
with 1 have written them. '

Therefore to come to the bufinefs : All Authorities of D^'
vine Writ which feem to oppofe this Opinion , are reducible
fix ClafTes : The firft is of thofe that affirm the Earth to ftand
fiill, and not to move: as ?faL 92. He fr anted the ronndl^^^^^

fure^that it cannot be mo^ed : AlCo ?fal. 104. Who l^^^^'^^

foundations of the Earthy that it pould not be remained for ever :

And Ecclefiaftes i. But the Earth abidetb for e-jcr : And others

of thclike fenfe.

Thefccondis of thofe which attcft the Sun to move, and

Kevolve

]38SSli

InV

HILOSOPHICAL

OMTROVfiR$IE$;

47P

t^evolvc aboutthe Earth; as PfaLi9. (b) In thmhath befet a OrlnScle
T^cibenuidc for the Snn, which comctb forth as a Bridegroom oHt ^^^^-^ wbernacu-

his chamber^ and rejoyceth as a Gyant to run his Conrfe. It him fuum, 4^c^;r-
*ometb forth from the uttcrmoft part of the lleai/en^ and runneth ^'^fj^ JJ^
(thnm iuno the end of it again'-, and there is nothing hid from the thorfolltTvetb.
f^cat thereof. And Eccleftaji.i. The Snn rifeth, and the Sun go-
^ih down, and hajieth to'the place where he arofe: it goeth towards
^be South, and tnrneth about unto the North. Whereupon the
Suns Rct/ogradation is mentioned as a Miracle, Ifaiah 38. The
Sftn returned ten degrees. And Ecc left afiicHS In his time the
S«'2 n-'cnt backward, and lengthened the life of the King. And
for this reafon it is related for a Miracle, in the Book oijofhnahy
that at the Prayers of that great Captain the Sun flood ftill, its
motion being forbidden it, by him ; Jofi.io. Sun fi and tboH
ftill upon Gibeon. Now if the Sun ihould ftand ftill, and the
Earth move about it, its ftation at that time was no Miracle j
and if Jofhuah had intended, that the light of the day fliould
have been prolonged by the Suns fplendour, he would not have
faid, Sun ftand thou pU, but rather Earth fiand thou fttU.

The third Claflis is of thofe Authorities which fay, that Hea-
Ven is abo'z^e, and the Earth beneath h of which fort is that place
of 7(7^, chap.2. cited by S. feter^m A^s.r^. 1 wiUJhew wonders
in Heaven above^ and ftgnes in the Earth beneath, with others of
^he like purport. Hereupon Chrift at his Incarnation is faid to
^ome down from Heaven \ and after his Refurreftion to have 4/-
^^nd,d up into heaven. But if the Earth (hould move about
^he Sun, it would be, as one may fay , in Heaven , and conle-
quently would rather be above Heaven than beneath it. And
^his is confirmed ^ For that the Opinion which placech the Sun in
^•^e Centre, doth likewifc place Mercury ^hos'^ the Sun , and
above Mercury , and the Earth above Ke.«., togeth^^^
^ith the Moon, which revolves about the Earth and therefore
^hc Earth, toge her with the Moon, is placed m the thud Heaven.

I» SphrtcaU

fics no more than to be neet to the centre, and ai;*^^, tna •
=>Pproach the Circumference, it muft needs follow, that tor ma- s„,. ,^
king eooi of Theological Pofitions concerning the Afcenfion
'ncfDe?cenfionof Chrift, the Earth is to be placed m^^^^^
tte, and the Sun with the other Heavens m the Circumtcrence ,
, anathebun.wuniiic Hypothefis inverts this

*na not accordmg to Copermcits , wiioii. r jr f (v,„fi„„ j
«rder.. with which one cannot fee how the true Afcenfion and
'^'^fcenfion can be confiftent. i ti n

The fourth Claffis is of thofc Authorities which make Hell to
in the Centre of the World, which is the Common Ofit>^^
«f Divines, and confirmed by this Reafon, That fince Hell Qta-

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2°K.B. 9,163

4^^

iktll ii it the
iemre *f the
Earth, not cf the
fVarU,

'Heaven And
EArtb are alyfays
nt'MUHllf oppofed
to each9tker»

j4fr(r the dky
ef Jad^mint the
earth (hall fiand
imm9vtable*

the (^4uthority 0/ S c r i p t u r

ken in itsftvift denomination) ought to be in the loweft part of
the World, and fince that in a Sphere there is no pare lower
then the Centre, Hellfliall be, as it were, in the Centre of the
World, which being of a Spherical Figure, it niuft fellow, that
Hell is either in the Sun (forafmuch as it is fuppofed by this Hy-
pothefis to be in the Centre of the World J) or elfe liippofing
that Hell is in the Centre of the Earth, if the Earth fhould move
about the Sun, it would neccffarily enfue, that Hell, together
with the Earth, is in Heaven, and with it revolveth about the third
Heaven^ than which nothing more abfuid can be laid or imagi'
ned.

The fifth Claflis, is of thofe Authorities which alwayes op-
pofe Heaven to the Earthy and fu again the Earth to Heaven j as
if there were the {ame relation betwixt them, with that of tb^
Centre to the Circumference, and of the Circumference to the
Centre. But if the Earth were in Heaven, it ftiould be on one
fide thereof, and would not ftand in the Middle, and confequent-
ly there would be no inch relation betwixt them j which never-
thelefs dorUftt only in Sacred Writj butevenin Common Spe^^^'
ever and every where anfwer to fach other with a mutual Oppo'
fition. Whence that of Genefi.- In the beginning God created
the Heaven and the Earth ; and PfaLii'yr .The Heai^en, e^^f^
the Hed'vens are the Lords hut the Earth hath he gi*ven to the
Children of men :. and our Saviour in that Prayer which he prc'
fcribethto us, Matth,6. Thy will be done in Earthy as it is in
Ueawn : ^ndS. Panlj i Corinth, 15. The jirfi than is of the
Earthy earthy -J the fecond man is of Heazien^ hea<venly : and
Colojf.i, By him were all things created that are in Hea^t^en^ and
that are in Earth : and again. Having made peace through the
Blood of his Crojfefor all things^ rvhether they be things in Earth
or things in Heaven : and Chap*^. Set your affect oris on things
abov not on things on the Earth with innumerable other lucn
like places. Since therefore thefe two Bodies are alwayes mn*
tually oppofed to each other, and Heaven, without all doubt,
reterreth to the Circumference, it muft of neceflity follow, that
the Eafrfh is to be adjudged the place of the Centre.

The fixth and laft Claflis is of thofe Authorities, which (be/^^g
rather of t athcrs and Divines, than of the Sacred Scripture) ^^X'
That the Sun, after the day of Judgment fliall ftand immoveable
in the Eaft, and the Moon in the Weft. Which Station, ^^.^ ,
P>^t/j4^<?r/t^ Opinion hold true, ought rather to be afcribed to
the Earth, than to the Sun i for if it be true, that the Earth dorh
now move about the Sun, it is neceffary that after the day or
Judgment u {hould ftand immoveable. And truth is, if ir
fubfift without motion in one conftant place, there is no realon

w*^y

P H I L O S O P H 1 C A L C O N T R O V E R S I E s}

^^'^y itfliould rathci ftand ill one fite of that Place than in ano-
ther, or why ic (liould rather turn one part of it than another to
Siin^ if io be that every of its parts without diftinftion^which
'^deftitutc of the Suns light, cannot choofe but be difmal, and
"^Uch worfe afFe£icd than that part which is illuminated. Hence
^llo Would arii'c many other abfurdities befidcs thefc.

Thefe are the Claffes, Sec. from which great affaults are made
^gainfi: the ftruSure of the Pythagorick Syfteme ; yet by that
['^^^e 1 {hall have firft laid down fix Maximes or Principles, as
^Impregnable Bulwarks creeled againftthem, it will be eafie to
^^tccr them, and to defend the Hypothefis of Pythagoras from
^ji^g attaqued by them. Which before 1 propound, I do pro-
*^^s (with that Humility and Modefty which bccometh a Chri-
'^ian, and a perfon in Religious Orders) that I do with reverence
f^bmit what 1 am about to fpeak to the Judgment of Holy
Church. Nor have 1 undertaken to write rhefe things oat of
^''•y inducements of Temerity, or. Ambition, but out of Charity
^nd a Defire to be auxiliary to my neighbour in his inquifirion
^fter Truth. And there is nothing in all this Gontroverfie
^^intained by me (that expe£i: to be better inftrufted by thofc
^ho profefs thefe Studies) which I fliall not retraft, if any per-
fons fliall by folid Reafons Sc reiterated Experiments, prove fome
^ther Hypothefis to be more probable^ but yet, until fuch time as
^^^y fliall decide the Point ,1 (hall labour all I can for its fupport.
My firft and chiefeft Maxime is this i When any thing is at-
tributed in Holy Writ, to God, or to a Greature, thats not be-
Jecming to, or incommenfurate with them, it muft of neceflity
received and expounded one, or more of the four following
^ayesj Firft, it may be faid to agree with ihcm Metaphoricallyy
^""d Proportionally, or by Similitude. Secondly, According to
'""^ manner of Confidering,Apfrehending,Conceiving,Vndi:rjland-
iinowing, &c. Thirdly , according to the Opinion of the
[""k^r^ and the Common way of Speakjng : to which Vulgar
^P^^ch the Holy Ghoft doth very often with much ftudy acco-
^^oJate it felf Fourthly, In refpeSl of our fel<ves, and for that
7 '''^ks htm felf HK^ nnto m. Of each of thefe wayes there are
^•^^'e examples : God doth not walk, fince he is Infimte and Im-
^^veable He hath no Bodily Members, fince he is a Pure Ad 3
confequently is void of all Paffion ofMinde', and yet m
7>*^d Scripture, Ge;/. 3. ^erf^^ it is faid, He walked in the coolof
'^'\^^y : a^d Job 22.ierfi^. it is faid, He rvalkcth inthe * Czr-
y.^fUeaJn : and in many other places coming departmg,
^'^'"ghaftisalcribed to God ^ and likewife Bodily parts, as
7^^^ Ears, Lips, Face, Voice, Gountenance, Hands, Feet,Bow-
Garments, Arms ; as aUb many PafTions, fuch as Anger,

p p p Sor-

481

« Circa Cardi-
nes Cacli.

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2°K.B. 9,163

482.

Luke i6»

The ^Htboritfof Scripture,

Sorrow, Repentance, and the like. What ftiall we fay there
fprc? Withoutdoubtfuch like Attributes agree with God (to
lafe thQSchoo\inens words Metaphorically^ Froportiofrally^ and by
SiMilitude: And touching Palfions, it may be faid, that God
condefcendeth to reprefent himfelf after that manner : as for
inftance. The Lord is angry , i.e. revcaleth himjelf its one that
is angry: He grieved'-) i.e. He revealeth himjelf as one ihat
is forroypfil : It repented him that he had made man ^ i.e. i^^'
Vied as one that repented. And indeed all thefe things are Covtt"
faratizfe adnos^ and in refpeft of us. So God is faid to be i^^
Heaven, to move in time, to fhcw himfelf, to hide himfelf,
obferve and mark our ftcps ^ to feck us, to ftandat the ^ooh
to knock at the door , not that he can be contained in a bodily
place, nor that he is really moved, nor in time *, nor that hutnan^
manners or cuftomes can agree with him, fave only according
our manner of Apprehenfion : This Conception of ours orderly
diftinguiflieth thefe Attributes in him one from another, wlie^j
notwithftanding, they are one and the fame with him : This Ap'
prehenfion of ours divideth alfo his afiions into fevcral tinieS)
which, neverthelcffe, for them oft part, are produced in one and
the fame inftant : And this, to conclude, alwaycs apprchendeth
thofe things with fomc dcfeft , which, notwithftanding are iH
God moft perfefi. For this reaf^n doth the Sacred Scripti^''^
^x^T^th It k\( according to the Vulgar Opinion^ whilft it afcribcs
to the Earth Ends and Foundations, which yet it hath not ,
the Sea a Depth not to be fathomed ; to Death (which is a Pfi'
vation, and confequcntly a Non-entity^ it appropriates A^'^o^;
Motion, Paflions,and other fuch like Accidents, of all which it is
deprived, as alfo Epithites and Adjunfts, which really cannot
fuit with it : Is not the bitterneffe of Death pafi ? i Sani.i ^-B^*
Let death come upon them^ Pfal He hath prepared the Infirw
ments of Death^ Ffal.7.14. Thouraifeji me from the gates O]
De^//?, Pfal.84. Inthemidji of the Jhadow of Deaths Ffal. 5?-
Lo^e is Jirong as Deatb^ Cant'.S.^. The Firji-Born of Deathjob
l^.l'^.DeJirHBion and Death fay ^<^c.]ob2^,22.Ai\d who kiov^'^
not that the whole Hiftory of the rich Glutton doth tonfift
the like phi afes of Vulgar Speech i So Ecclefiafticus^ Chap- ^7'
verf li. The godly man ahidtth in wifdome^ as the Sun ba^^
fool changeth as the Moon •, and yet the Moon according
real truth of the matter no wayes changeth, but abides the f^^^^^
for cvcY^ 2LS JJironomers demonftrate , one half thereof i*^^^^^^'
ing alwayes lucid, and the other alwayes opacous. Nor at any
time doth this ftate vary in it, unleffe in refpeSf of usy and ac-
cording to the opinion of the Vulgar. Hence it is cleer, that the
holy Scripture fpcaks according to the common form of fpew^di u-

thi

net
the
the
anc
anc
fai(
fee.

fen
the
fee
hit

«nl
'» ,

to
op
th
is
E:
th
N
oi

/
c

{

/« PhILOSOPH ICAL

Controversies:

483

amonglctheunlcarnca, --^ ^^'^'^'^^'^J^^^ 'Ekem'an-
.hings, and -c acco^jnjj - ^^^^^^

fa-] Sr^rof an, and U followeth in
e tSc And the E'vcmng and the Morning n,ade ,he firjl r^;, :
ndl?h ie afce thcfcvcral Afts of the Creation are d.ftmgu.fted

'oy,i„,gof »m''8«""™™'fV't° and not according to

"r ' txtrTcvrn^:rbS{'h..ven. .^n

Fi.ll therefore , U tne , • f ^e diftinaion

of Day and Nigiit- noCffikftial Body can be moved

of thclemcn,who aflKm th^^ n^^^^^^^ ^

Unleflb per acadcns, and oy tn ^j^^^
.KyaI;dNigta.Motninga„dE,cni„^^^^^^

Of all other light, but that of ^l^^/""' /fo, that the Suns
("which is their "'Ip^co^^^^ Body , unlefs a ve-

light pafleth over but ^J^^/i^/bS .he/ Le iHumina-

tyfmalhnatter J^^^.r halfreS da* ^"^^

tedby the Suns alpea, the otha half remaimng^ own Body.

Wofe by reafon of a ^^^^.^^ P'^^^^f 1 S^of heaven, ac-
Therefo/e the diftina.on of f y« ^J, f3 ScriPt.ues, muft
cord.ng to the delcr.ption of them in the faaed be P

Jotbe^ndcrftood.Y^W^;^-'^^-:^^^

/e/f, butinrelpca of tt'<^Ear_tb, ana ^^^^^^^^^^^^

confec^uently [ccnndHm nos. 1 s n ^^^^^^^

and rci Ai^jo^'^^^'y ^

PPP ^

Alia funt notio-
ra nobis, alia, no-
tion natura, vel
fecundum fe>

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2°K.B. 9,163

Authority 0/ Scripture

And if any one would underftand thefe Days of faced Scii-
pture, not only fccnHdum ms, but alfo [ccundnm naturam^
circulations of Coeleftial Light returning to the felf lame po »^
from whence it did at firft proceeds fo a» that there needs n
» u rcfpea to be had to Night or to » DarknelTe, for which lole rea
. Auudumb^m jclpec^ ^^.^^ .^j^B ^j^^ Interpretation of faercd Scr.ptu

fecHndumtios ; In oppofition to this we may thus argue : » '
facred Scripture beunderftood to fpeak abjolutcly, of iterate
and fucceffive circulations of light, and not refpcaH nofln , a3
thcfe words Evening and Morntng had never been inicrtea,wluci
in their natural acceptation denote the Suns habitude to us and t"^
the Earth.- For that the M#»«/«^ is that time when the Sun be-
gins to wax light, and to rife above the Hon'x.on in the
and become vifible in our Hcmiffh^re, and E'Z'cnng is the tiiB^
in which the Sun declines in the Weft, and approacheth with u»
light neerer to the other oppofite Horizon and Hemifplutf^'
which is contiguous to this c f ours. But the word Day is a Co -
relative to the word mght. From hence therefore it evidently
appeareth, that thefe three words Evening, Morning, aad Vay,
cannot be underftood of a Circulation ot Light fcciu'dumJCi
and abfolute, but only fecundum nos, and refpcBu nofirt ■■> an
that fenfe indeed the Morning and Ei^ening do make the i> i,

''"in^ike manner, Gc«.l. i6.it is [^\6,Cod made trro great Lr^/-"^i
the greater Light to rule the Day, and the hfcr Light to rule
hight, and the Stars. Where both in the Propofition and in tn-^
fpccification of it, things are fpokcn which are very difagreemg
withCoeleftial Bodies. Therefore thofe words are in that place
tobe iutcrpfetcd according to the forefaid Rules ; namely, ae-
cording totficthird andfourth; fo that they may be faidto be
nnderaood according t(, the fenfe of the 'vulgar, and the cown
waj^of freaking, which is all one, as if we (hould lay, /''"'"J;"
apparentiant, and feaindtm nos, vel refpeBn nojiri. For tirit,
is faidjn the Propofition, And God made two great
meaning by them the Sun and Moon, whereas according to t
truth of the matter thefe are not the Greater Rights i For a
though the Sun may be reckoned amongft the Greater, the M
may not be fo, unlefs in refpeB of m. Becaufe -yno.'.^,
thofe that are abfolutely the Greater, and a little leflcr than
whici MeuAli, Sun Cnay a manner equal to it ) and far bigger than the JVi '
wemV with great reafon enumerate Saturn, or lo."e- J.,-^
Fixed Stars of the firft Magnitude, fuch as Canopm, (oij^' .^^
calkd".irr<»«rfr ) in the end of a River ; or the Ltttle 1^^^
the mouth of the Great Dog ; or the Foot of Orion, cal'ea
gel i or his Kight Jhoulder, or any other of that Mag^'

ill

011

lie

he
'lie

dc.

/^ipHILOSOPHlCAL CoNTROVERSiEs} 4^^ /

Therefore the two great Lights are to be underftood in refpeft of
^s, and according to vulgar eftiination, and not according to the
true and rcall exiftence of fuch Bodies. Secondly, in the fpeci-
fication of the Propofition it is faid. The greater Light to rule the
3 hereby denoting the Sun j in which the verbal fcnfc of
Scripture agreeth with the Truth of the Thing ^ For that the Sun
is the Greateft of all Luminaries, and Globes. But that which
followeth immediately after , Afnl the leffer Light to rule the
^ight^ meaning the Moon, cannot be taken in the true and real
fenfeof the words: For the Moon is not the lelfcr Light, but
Mercnry-j which is not only much lelT^fr than the Moon, but alfo
^Han any other Star. And if, again, it be faid, That the Holy
Text doth not fpeak of the Stars, but onely of the Luminaries,
for that prefently after they are menti >ned apart, And the Stars'^
^nd that what we fay is true touching the comparifon of the Stars
^mongft tbemfeives, but not in refpcft of the Luminaries, name-
the Sun and Moon : This rcpjy doth difcover a man to be
Utterly ignorant in thcfe Studies, and fuch who having not the
l^aft fmattering in them, doth conceive an abfurd and erroneous
Opinion of the Cocleftial Bodies. For the Moan and Sun, con-
fidcrcd in themfelves, and as they appear to us, if they fliould
a far greater diftance from us, than indeed they arc, would be
no other, nor would appear to us otherwife than Stars , as the
Jeft do in the Firmament. But Great Luminaries they neither
^r., norfeemtobe, {2iWc only in refp Si of hs : And fo, on
^tic other fide, the Stars, as to themfelyes, are no other than fo & the [amc thing.
^^^iT^y Suns and fo many Moons \ yet are fo far remote from us,
^hat by reafon of their diftance they appear thus fmall, and dim
light, as we behold them. For the greater and lefler diftance
^ heavenly Bodies (ceteris parihus ) doth augment and diminift
^l^eir appearance both as to Magnitude and Light. And there-
W the words which follow in that place of Genefij, And the
^^^rs (as diftinguirtiing the Stars from the Sun and Moon J) are*
l>c taken in no other acceptation than-that which wc have fpo-
"^^^ of, namely, according to the fenfe of the Vulgar^ and the
'^>nmJn manner of ffeech. For indeed, according to the truth
the matter, all Cocleftial Bodies, being (hining Globes, are of
^vaftbignels' to which it we fliould be fo neer as we are to the
Moon, they would fccm to us of as great, yea a greater magni-
^^de tfcan the Moon : As likewife on the contrary, it we were as
''^'^diftant from the Sun and Moon, as we are from them, both
^^on and Sun would fliew but as ftars to us. And yet the
Splendor of the Sun would doubtlefs be greater intenfwe than
^^^t of any other ftar. For, although it fliould be granted that
f^me ftars (as thoie of the Fixed that twinkle) do ftiine of thcm-

felvcs

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2°K.B. 9,163

felves. aud by thcif own nature, as the Sun, that denvcs rot
5 fiornoth'ers (.hich yet remains -decided and doub W
and borrow not their light from theStmi ^'''''^f^'\^ZsL
brightnefs of none of the ftars may becomparca vvuh the Sun

Star

ced in the lame proximity to us with the Sun, atrd theiefo.^ ap
pearing to us of the fame Magnitude as the un, can beftow up
Sn us lo much Light as we receive from the Sun : As on t
contrary, the Sun, at the fame remoteneffe from us as they are,
would indeed, as to its Magnitude, appear to us as one ot t n
ftars, but of a fplendour much more than that of thei •

n. B.nh « So that, now, the Earth is nothing elfe but another Moon or IWr,
uUr ^.n . \ ,o us, if we ftould behold It ftom a con

venient diftance on high. And in it might be obferved (m tha
variety of Light and Oarknefs which the Sun pr oduceth m it by
making Day and Night) the fame difference of Alpeds that a.
fcen in the Moon, and fuch as are oblerved ui tricorporat e

in like marker alfo 'trs very probable that the (ame n.gl J
bedifcernedinother Planets, which Ihineby no hght ot t
own , but by one borrowed from the Sun. What evc tner
fore may touching thefe matters be delivered m the iacred Leav
o°d.e common fpeech of men, d.ffenting from the real tn tlr ^
ought (as we have faid before) abfolutely to be received andun
ii:riiOQ&fecHndtimi>HlgifententiaM, ^ conimuncw loquendt <(J

cenciPiendiftylttm. r t n i- rj i the

Andfo, to return to our purpofe, if, all this con fidered, tn
FythajToriatt ommoabcttae, it will be eafie, accordmg to t
fame Rule, to reconcile the authority of faered Scriptures wub
it, however they feem to oppofe it, and in particular thole o
fi^ft and fecond Claffis, fctUcet by my firft Maxtmc : For tn
thofe places the holy Records fpeak according to our n;ann
underftanding, and according to that which appeareth tn i ci)^ j
of usi For thus it k with thofe Bodies, incompartjon of
wh, ,he Su„r, , defcribed by ihe -vulgar and commune way of htn' „
. « « . J . I ^^^^ E^,,,, ^ ,f r^ere fiand.ngp

andimmo'.cablc, and the Sun, astf ^t were arcnmambientj''
her. - And fo the Holy Scripture is ufed in the Commune

move^ & r.ot th
Earth,

Vulgar way of fpcaking ; becaufe in relpeft of om figh^'
Earth feems rather to ftand fixed in the Centre, and the ju ^^^^
circumvolve about it, than otherwile : as .t happens to tho'
are putting off from the Banks of a River to whom the
f«in* to move backwards, and go from them : but they
perccive(which yet is the truth)that they thcmfelvcs go ^

VV
fes
Pe
Pc

?
(lis

let

ofi

tru

tai
ih

f'
th

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2°K.B. 9,163

he
tb
he
io
of

lid
\«C

nil
mt
nd
he

ds.

/» Ph ILOSOPH I c AL Controversies.
Which fallacy of our fight is noted, and the Reafon thereof af-
figned by the Optlcks ; upon wich, as being ftrange to, and be-
fides my pnrpofe, I will not ftay) and on this account is Mneas
brought in by Virgil, faying ;

Frovehititttr portu, tenx<iue Hrbefque recedutit.
But it will not be amifs to confider why the facrcd Scripture

487

comply wich tl

f the Vulgar, and

ipinions

why it doth not rather accurately inllrua men in the truth ot the
. matters and the fecrcts of Nature. The Reafon is, firft, the bc-
H^nignityof Divine Wifdome, whereby it fweetly accomodates it
Prf'^'f to all things , in proportion to their Capacity and Nature.
I Whence in Natural Sciences, it ufeth natural and neceffary cau-
I fes, but in Liberal Arts it workcth liberally, upon Generous
■ ftfrfons after a fublime and lofty manner ; upon the Common
I People, familiarly and humbly i upon the Skilful, learnedly ;
I upon the Simple, vulgarly i and foonevery one, according to
P his condition and quality. Secondly , becaufe it is not its In-
" tention to ail our mindcs in this life with vain and various curi-

ofities which might occafion our doubt and fulpenfe., tor the W EcdeU.i.r.
truth is, C^?; We that iticreafelh knowledge, tncreafeth forrow. "'■
Moreover it did not only permit, but even decree , thatth e
World Ihould be very much bufied in Controverfies and Difpii-
t4tions, and that it (hould be imployed about the uncertainty of cl>»f.z v.iu
things i according to that faying of Eccleftaftes (b) He hath
h the WurU in their heart -, fo that no man can find out the work,
'''at Ged ma keth from the beginning nnto the end. And touching
thofe doubts, God will not permit that they ftall be difcovered ^cor.M.r^.j
tons before the endof the World: CO Atwinchtme hew.U
hring toUohtthe hidden thing, of darkneffe .- But Gods onely
fcope in the facrcd Scripture is to teach men thofe things which
conduce to the attainment of Eternal Ufei which having ob- Cor.r.ij.v.
taincd, (d^ We Pall fee hm face to face : and JhaU be ^^^-^ ■

I'ke him) for weLu fee Inm as he is. Then fliall he clearly a ,
fr^on make known unto us all thofe Curiofities, and Dogmati-
cal Oiieftions, which in this life. CD in winch we fee through a (/O.Cor.c.13...
Claffe darkly could be known by us but imperfeaiy and^^ pofle-
riori, and that not without much pains and ftudy. For this
caufe the Wifdome of God, revealed to us in the lacrcd Leaves,
's not ftikd Wifdome abfolutcly, but (g) Samng ff^tjdome ; ^)p„,,fi,rt.,5 .3
Its onely end being to lead us to falvation. And S. F aul preach-
'ngtothc Corinthtans, (iith ; (h) I determined to know nothing (h) iCot.cr.z-r
'imoijg you, favejeftts Cbrifl-,andhim crucified: whereas ooc-
^ithftandi'ng he was thorowly inftruQed, and profoundly learned

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2°K.B. 9,163

^88 Tbe Authority 0/ Scripture

in all humane Sciences , but making no account of thcfc things
he protcflcch that it was his defire to teach them no more but the
way to Heaven. Hence is that which God Ipcaketh to us t)/
(0 Ii*a»r.^8.v. 17. ij^aiah^ (t) Ego Dominus Dens, docens te utiha [I am the Lord
thy Cod which teacheth thee profitable ihivgs:^ VVhere the Olof-
fary addcth, non fuLtiUa [not fubtil tics.] tor God neirhcr taught
us. Whether the Materia Frima of Heaven, and the Elements
be the fame ^ nor Whether Continnal be compofcd of Indivifi-
blcs, or whether it be divifible in lufifiitum ; nor, whethci:
Elements are formally wixt nor how many the Coelcfti^l
Spheres, and their Orbs are i Whether there be Epicycles ot
Eccentricks , nor the Vertucs of I^lants and Stones , nor cheN^'
tureof Animals , nor the Motion and Influence of the Planets i
nor the Order of the Univerfe j nor the Wonders ot Minerals,
and univerfal Nature : but only [ntilia :~] things profitable ,
wit, his Holy Law ordained to the end, that we being put inr<>
pofTcflion of Bleflednefs, might at length be made capable of 2II
perfeft knowledge, and the vifion of the whole Order and ad-
mirable Harmony, as alio the Sympathy and Antipathy of the
Univeifc and its parts, in his Wordy wherein all t'^^
things (hall moft clearly and diftinSly, then, appear to us, vv'}^;^"
mean while, in this life, he hath remitted (^as far as its ability
reacheth) to humane fearch and enquiry : But it was not h'^
purpofe to determine any thing, direftly or indireflly, touching
the truth of them. Becaufe as the knowledge thereof would lit'
tie or nothing profit Us, but might in fomc cafes prove prejudi-
cial i fo the ignorance thereof can doubtlefs be no detriment?
but may in fome cafes be very beneficial to us. And thc^cfo"^^
by his moft admirable Wifdome it comes to pafs, that though all
things in this World are dubious, uncertain? waverings P^^"
plexed i yet his Holy Faith alone is moft certain ^ and althoiigu
the opinions about Philofophical and Doftrinal points be diveiS;
there is in the Church but one Truth of Faith and Salvation-
Which Faith, as necefsary to Salvation, is fo ordered by pivui^
Providence, that it might not only be indubitable, but alio lUi-
fliaken, fure, immutable, and manifeft to all men : the iufallih^^
Rule of which he hath appointed the Holy Church, that is vv'^^|^^
ed with his precious Blood, and governed by his Holy Spirit 1
Thtff 4. whom belongs our Sanftification, as being his work. This ih^^^'
' fore is theReafon why God would have Speculative O^^^f^^^

which nothing conduce to our Salvation and Edificatiouja^d /
the Holy Ghoft hath very often condcfccnded to Vulgar Opu^^^
0ns and Capacities, and hath difcovered nothing that is fu^gt*
or hidden to us, befides thole things that pertain to Salv^tton^
So that confequcntly it is clear by what hath been faid, hoW

wn>

why
thor
alfo
the
Aut
and
I

this
thit

an.
ith
irit
the
the
am
bei
bei
ma
ev(
ed.
M(
an<
tnc
^In
Ho

tr
th

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2°K.B. 9,163

Phi L osoPHic AL G ont rov ^ksie s;

4S§

why nothing of certainty can be evinced from the forefaid Au-
thorities to the determining of Controverfies of this Nature i as
alfo with what Reafon from this firft Axiome the Objeaions of
tHe firft and fecond Claffe arc cafily anfwercd, as alfo any other
Authority of facred Scripture produced againftthe Fythagonan
»nd Cobernican Syftemc fo long as by other proofs it is true.

And the Authorities of the fecond Claffe in particular by
•his fame Maxime, Of the ordinary manner of apprehending
tbingf as they appear to m, and after the common way of fpeahc
i»g, may be thus reconciled and expounded; namely, Oftentnnes
an Agent is commonly ,and not improperly faid to move, (though
whave no motion) notbecaufe it doth indeed move, but by ex-
innfickdenomination, becaufe receiving its influence andaaion ac
»he motion of the Subjeft ; the Form and auality infufed to
the Subiea by the faid Agent doth likewife move. As tor ex-
ample, a Fire burning in a Chimney is an immoveable Agent,
before which a man oppreft with cold fits to warm himfelf who
being warmed on one fide, turns the other to the Fire, that he
may be warmed on that fide alfo, and fo m like manner he holds
evel-v part to the Fire fuccelfively, till his whole body be warm-
cd 'Tis clear, that although the Fire do not move, at the
Motion of theSub)c'a,towittheMan, who recciveth the heat.
»nd aaion of the Fire, the Form and auality of its Heat doth
taove ftngnlatim, & per partes, round about the mans body, and
*Wayesfeekethoutanewplace and fo, though the Fire do
not move, yet by reafouor its.efFea, it is faid to go lound all
the parts of the Mans body, and to warm it, not indeed by a
true and real motion of the Fire it felf, fince it is fuppofed (and
that not untruly) not to move, but by the motion to which the
^odv is excited out of a defire of receiving the heat of the Fire
meachof itsparts. Thefamemay be applied to the Illumina-
tion tprX^ on the parts of any Globe, which
move TSarly at the afpea of a ftuning immoveable
Light. Andt the fame manner may the Sun be faid to rife and

>>pon which ground he is truly faid (fccHndnm ^« ^^^^^^
"e«.) to movl. above, and revolve about the Earth . Not *h^^^^^
Sun doth move, (for by this Opinion we affirm the Earth to
movc^hatitmay^receiJe the S^n one whi e in one, another
^hile in another part of it) but that^uhe motion of the Earth

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2°K.B. 9,163

490

Jofliua f, 10.

12.

Ifa.C.38.

The ^ntbority o/Scripture,

her felf a contrary way, the Quality difFufcd into her, and im'
preffed upon her by the Sun, namely the Light of the Day
moved, which rifcth in one part of her, and fets in another con-
trary to that,according to the nature and condition of her motion,
And for this veafon the Sun it felf by confequence is faid to nle
and fet, (which notwithftanding ex Hypothefi ftands immovea-
ble) and that no otherwife then fer donominationew extrinfecam,

as hath been faid. j i^u

After this manner the command of Jojhuah ^ Sun ft and tnoi*
fiiU, and the Miracle of the Suns celTation of Motion wrougn*:
by him, may be founderftood, as that not the Solar Body pr^'
perly, but the Suns fplendour upon the Earth flood ftill 5 fo that
not the Sua it felf, (being of it felf before that time immovea^
ble)but the Earth that receiveth its fplendour, flayed her M^*
tion ; which, as fee inceffantly purfuing her ordinary Motion to-
wards the Eaft, * called up the Light of the Sun in the Weft,
ftanding ftill, the Suns light impreft upon it likewife flood ftil'*
After the fame manuer proportionally is that Text of IfaiabcS-
plained, touching the Suns going ten degrees backward upon tji^
Dial of Aha'i*. So (which may ferve for another Example)
Hand being moved about the flame of a burning Candle that
ftands ftill, the Light moveih on the Hand, that is to fay^ ^nc
faid Hand is ilhaftrated now in one part, anon in another, whcii
as the Candle it felf all the while removes not out of its pla^^^ '
vih^u^on per detJominatiotJem extrinfecant^ the faid Light Hiay
be siffirmed to rife and fet upon the Hand, namely, by the f^>l^
motion of the faid Hand, the Candle it felf never moving all the
while.- And let this fuffice for the explanation of my firft Pfi^J'
ciplcef Mtf3ei?»<f5 which by reafopo its difficulty and extraordi-
Hafry weight ^equitn^d feme prolixity in the handling of it.

MyfecondMiiximeisthis^ Things both Spiritual and Cor-
poreal, Durable and Corruptible , Moveable and Immoveable,
haVe teceived from Cod a perpetual, unchangeable, and inviola-
ble Law,conftitutingthe Eflence and Nature of every ^>'^c ^*
them : according to which Law all of them in their own N^"
re perfifting in a certain Order and Conftancy, and obferving
e fame perpetual Courfe, may defervedly be ftiled moft Stable

tn
the

and Determinate. Thus Fortune (than which there is nothing
in the Worldmoreinconftant or fickle) is faid to be conft^/^^
and unalterable in her continual volubility, viciflitude , a^^J
conftancy, which was the occafion of that Verfe,

Etf tmper cortftdtts in levitate f \tA eft.

: ill -i'nv.

And thus the Motion of Heaven (which by the conftan ^av^

HILOSOPHICAL

N T R C V E R S I E S;

or-

ing

ing
int

of Naciue ought to be perpetual) rtiay bcfaid to be immutablfe
and immoveable, and the Heavens themielvcs to be immovca-
% moved, and Tenene things to be immutably changed, be-
wurcthofc never ceafe moving, nor thefe changing. By this Prin-
<:''ple or Maximc all difficulties belonging to the firft Claffis are
•cleared, by which the Earth is faid to be ftable and immoveable,
that is, 'by underftanding this one thing, That the Earth, as to its
own Nature, though it include in it felf a local Motion, and that
'•>feefold, according to the opinion of Cofermcus (fcilicet Diur-
with which it rcvolveth about its own Centre ; Annual,
which it moveth through the twelve Signes of the Zodiack,
ind the motion of Inclination, by which its Axis is alwayes op-
>ofcd to the fame part of the World ) as alfo other Species of
^iutation, fuch as Generation and Corruption, Accretion and
I^iminution, and Alteration of divers kinds; yet in all thc^e (he
's ftable 8c conftant, never deviating from that Order which God
•^"h appointed her, but moveth continually, conftantly and im-
mutably according to the fix before riaraed Species oPMotion.

My third Maximcfliall be this i When a thing is moved ac
cording to feme part of it, and not according to its Avhole , it
cannot be laid tobc fim^ly & ahfolntely moved,but only per ace
dens for thatftability taken fimply abfolntly do rather accord
With the fame. As for example, if a Barrel or other meafurc of
Water be taken out of the Sea, and transferred to another place,
»Ke Sea may not therefore ahfolutdy & fmfly hc faid to be remo-
Mfiom place to place*, but only per Accidens, and fecundHm
that is, according to a part of it, but rather (to fpcak fim-
Ply) we (hould fay that^hc Sea cannot be carried or moved out ot
proper place, , though as to its parts it be moved, and transter-
to & again. This Maxime is manifeft of it fclf,and by it may
^ Authorities be explained which feem to make for the ,„„ma-
l"Hty of tlie Earth in ?his manner namely, The Earth ferfc&.
"Y^/'tf^confideredasto its Jf^W^ , is not mutable, j«ing it is
"either generated nor corrupted neither increafed nor dimimfhedi
'^^•theris iiihcrcd fccundimtotum^ but on\y fecHndnm partes
^'°vv it plainly appears, that this is the genuine and true Senfe of
-^•hatisS^^o^toutofEcc/e^^.^^^^^
P^Pth ar.ay,and another Generation camethM theEarth abjdeth
/■"^e.er: as if he (hould fay; although the Earth according to Us
P^rts, doth generate and corrupt,and is liable to the vicfluudes of
Wration^and corruption, ycr in reference to its Whole it never
§^neratethnor Corrupteth , but ^^b'deth immutable for ev r :
L>ke »3 , Ship, which though it be mended one while in the Sail-
y»rd, another while in the Stern, and afterwards mother parts
"yet remains the fame Ship asit wasac firft. But tis to be ad.

491

r Several Aiot'ms
of the Earth ac
carding to Copcr-
nicus.

The Earth Se-
cundum Tocum ii)
Immutable't
though not Immh
vahle^

ver

tiferf

49'

The Edrth caw

not Secundum To-
tum, remove out of
its Ndtnral Place.

The Natural
Place of thcEartbt

The Moon is 4h
\/£tberial Sodj,

The (Authority o/Scripture,

vertlzed, that that Scripture doth not fpeak of a Local Motion?
but of Mutations of another nature^ as in the very fiibftance,
quantity or quality of the Earth it felf. But if it be faid, that
it is to be underftood of a Local Motion, then it may be ex-
plained by the infuing Maxime, that is to (ay^ a rcfpcft being h^
to the natural Place afligned it in the Univcrfe, as ftiall be fhevve
by and by.

The fourth Axiome Is this ; That every Corporeal thing,
veable or immoveable from its very firft Creation, is alorted
proper and natural place , and being drawn or removed ft^^'^
thence, its motion is violent, and it hath a natural tendency
move back thither again : alfo that nothing can be moved fr^j^
its natural place, /er/i//^/ii;;/T(9^«w, For moft great and dreao'^*
mifchiefs would follow from that perturbation of things in
Unlverfe. Therefore neither the whole Earth , nor the wh^^^
Water, nor the whole Air can fecupdum tot urn be driucn or i^^"
ced out of their proper place, fite, or Syftcme in the Univen^'
in refpeft of the order and difpofition of other mundane Bodi^-'
And thus there is no Star (though Erratick^ Orb or Sphere th^^
can defert its natural place, although it may other wife have fotn^
kind of nK>tion. Therefore all things, how moveable /^^y^^^'
are notwithftanding faid to be ftable and immoveable ii^ ^^^^
proper place, according to the forefaid fenfe, i.e. fecunduttt to*
tum j For nothing hinders, but that fecundum partes they
fome waymove ^ which motion fliall not be natural, but vlol^^^'
Therefot^ the Earth, although it fliould be moveable, y^^
might be faid to be immoveable, according to the precedent
Maxioie, for that it^ neither moved in a right Motion nor out
the Courfe aflign«d it in its Creation for the (landing Rule of i^^
motion i .hut keep within its own fite, being placed in that
which: is- called the Grand Orb, above Venm^ and beneath Mars^
and being in the middle betwixt thefc (which according
common opinioa is the Suns place) it equally and continually
moveth about the Sun, and the two other intermediate Planet^?
namely Venus and Mercery, and hath the Moon (which is anotn^^
Earth, but ^therial, as Macrobius after fome of the ancient P^t'
iofophers, will have it) about it felf. From whence, inafmuch^^
flie perfifteth uniformly in her Courfe, and never at aay ^i^^
departeth from it, (he may be faid to be ftable and immoveaP ^'
and in the fame fenfc Heaven likewife , with all the Elein^^^^^
may be faid to be immoveable. ,

The fifth Maxime followcth, being little different (ro^
former. Amongft the things created by God, fome are of f^^j! ^
i^ature, that their parts may be ab in<vicem^ or by turns?
parated from themfelves , and dif joyned from their

h Ph iLOsopH I C AL Controversies.

493

tt9

im
to
fin
ful
he

[IlC

eir

nr.
it

lat
r/,
he

iiy

ts,
icr
bi-
as

le-.

he
la
e-

others may not, zt lc3i&, tzkca coUeSfively. now thofe arc pc
f"fhablc, but thefe perpetual. The Earth therefore fince it
*s reckoned amongft thofc things that are permanent, as hath ^^^^^^^^^^^^
'^ecnfaid already, hath its parts, not diflipable, nor ab inuicent^ ,„ „
fcparable floni its Centre (whereby its true and proper place is »sN»t«,*ivu».
»fligned it) and from its whole, taken collcaively : becaufe ac-
cording to its whole it is always prefcrved, compaa, united, and
tohxrentinitfelf, nor can its parts be feperatcd from the Cen-
tre, or from one another, unlefs it may io iz\\ oxxt fer accldens,
»nd violently in fome of its parts v which afterwards, the oWtaclc
Ijeing removed, return to their Natural Station fpontaneoufly,
»nd without anyimpulfe. In this Senfe therefore the Earth is
'aid to be Immoveable, and Immutable : yea even the Sea, Aire,
Heaven, and any other thing (falthough otherwife moveable) fo
'ong as its parts are not diflipable and feperable, maybe laid to
Immoveable , at leaft taken coUcoii'vely. Tbs Principle
or Maxim difFereth from the precedent only in that tbjs refcrrs
to the parts in order to Place, and this, in order to the Waole.

From this Speculation another Secret is dlfcovered. For hence ^^-^ fj-
'Usmanifeft wherein the proper and genume tormality ot the „hatui.
Oravity aad Levity of Bodyes confifteth ; a point which is not fo
clearly held forth, nor fo undeniably explained by the Penpate-
tick Phylofophy. Gramty therefore is nothing elfe according to
Principles of this new Opinion, than a certain power and ap-
Pnite of the Parts to rejoyn with their Whole, and there to reft
*s in their proper place. Which Facuky or Difpofition is by
E>ivine Providence beftowed not only on the Earth, and Ter-
rene Bodies, but, as is believed, on Coeleftial Bodies alfo, name- fC«f'f^^^
h the Sun, Moon, and Starrs ; all whofe parts are by this Impul-
fionconneaed, and conferved together, cleaving clofcly to each
°ther, and on all CdespieQlng towards their Centre, untd they
come to reft there. From which Concourfe and Compreffion a
Spherical and Orbicular Figure.ofthe Csleftial Orbes is produ-
, wherein by this occult auality naturally incident to
«>chofthcmtheyofthemfelves fubfift, and arc alwaycs prefcr-
"^^^ Bat Lc^i/v is the Extrulion and Exclufion of a more te-
nuofeand thin Body from the Commerce of one more Solid and
<J^nfe, that is Hctero^eneal to it, by vertue of Heat. Where-
"Pon, as the Motion of Grave Bodies is Compref've, io the Mo-
tion of Light Bodies is Extcnfi've : For its the propperty ot Heat
to dilate and rarify thofe things to which it doth apply, conjoine
communicate it felf. And for this reafon we hnd Levity
''nd Gravity not only in refpcaof this our Teteftnal Globe, and
tl^e Bodies adjacent to it, bat alfo in refpeft of thofe Bodies
^hich are faid to be in the Heavens, in which thofe parts wW^W

Comf re five Mo-
tion , f roper to
Gravity, th: Ex*
tenjtve^ to Leiitjl

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2°K.B. 9,163

7be Antbority 0/ S g r i p t u a s

by rcaion of their proclivity m^ke towards their Centre are
Grave, and thofe that incline to the Circumference Light. An
foin the Sun, Moon, and Starrs, there are parts as well Crave as
Be^v£H is not Light. And confequcntly Heaven it felf thatfo Noble Body,
E}!:I:%:if andcfafifthEfrence^niallnotbeconftitutedofa Matter dilif^
fron, the matter of rent ftoiH that of thc Elcmcnts, being fice from all Mutation i
infcTfor Bodies. -^.g Subftauce, Qiiautity, and Quality: Nor fo admirable an
Nor jet a Solid excellent ^s Arifiotle ^^owld make us to believe*, nor yet a ioU
ordenfe Body bnt g^j and impermeable and much leffe ( as the generality ^>
men verily believe) of an impenetrable and moft obdurate D^n-
fity : but in it (as this Opinion will have it) Comets may be ge-
nerated ^ and the Sun it felf, as tis probable, exhaling or attract-
ing fundry vapours to the furface of its Body, may perhaps pro-
duce thofc Spots which were obferved to be fo various, and iif^'
* DelleMacchie -^^ VifcHs : of which GaliUns in a perticular ^ Trcauic

hath moft excellently and moft accurately fpoken ; infomuc^j^
that though it were not bcfidcs my prefcnt purpofe, yet it is con-
venient that I forbear to fpcak any thing touching thofe n^^^^^^^^^
leaft I (hould feem to do that which he hath done before me : 1^
now if there be found in the Sacred Scriptures any ^"^'^^'^[^^^
contrary to thefe things , it may be falved by the forefaid A|;g^^^
ments Analogically applyed. And furthermore it may be ^i^^
thatthat Solidity is to be founderftood, as that tt admtts oj
'vacHum^ cleft, or penetration from whence the leafi 'vacuity Pttg
proceed. For the truth is, as that cannot be admitted in boa» J
Creatures, fo it is likewife repugnant to Heaven it felf, b^^^S
indeed a Body of its own Nature the moft Rare of all
.VnimCorp^ri^ thers, and tenuofe beyond all Humane Conception, andhappjy
ftmpiicis.HnHieji ^^^^ ^^^^ ^^^^^ proDortiou to the Aire, as the Aire to tn^

huic fpecics. Water. nrdsof
%eEiui&OrcH- is clear alfo from thefe Principles how falfe thcie w'o»
\ St Ar^^^otle are. that : Of one fimple Body, there u one f^f^^^^^^^^^

ad medinm ; p*-

and this is of two kjndes^ Right and Circular : the R igt^^ ^
Z'^&'i^t^t' fold, from the medium, and to the medium ; the fir ji of Light ^^^^
cmdui j^ravium, dycSy as the Aire and Fire : the fecondof Cra^ve Bodyes ,
Z^'^arfnUrT ^^^^^^ ^^^^^^ ' ^^^^ Circular, which is about the medium, ^^.^

circa Ztdt- \ongeth to Hea*z/en, which is neither Gra've nor Light : For ai
umcompttitCcsh, phjiofophy is ,iow forfakcn, and of it felf grown intodifeit^ '
f::^:::!;:^. for though it be received for an unqueftionable truth in this n^^.^
And. dc c«/,. Opinion, that to a fimple body appertains one only ^'^"F^ j^j^e

'r^deCoper^i. on,yet it granteth no Motion but what is Circular,by w^iich a
cHmdeR'voiHtio. afimple body is confcrved in its naturall Place, and lublJl^s

Unity, and is properly faid to move [ocolin aplace:]^^^^^^
peculiar to only It Comes to pals that a Body fof this tcafou doth contiuue ^.^^^
Simple Ma. jt felf, [or about its own jx/J",] and although it have a ^

its

h Philosophic al Controversies.

n it abideth ftill in the fame place as if it were perpetually im-
moveable. But right Motion, which is properly *^ locnm Ito a
fWe] can be alcribed only to thofe things wh.ch are out of the.r
"aturall place, being far from union with one another, and from
unity wi?h their whole , yea that are feperated and dmdedfrom
it : Which being that it is contrary to the N*;"'^-"^ f
^ Univerfe, it necelfarily followeth, that right Motion doth m
Jortfucewiththofe things wW^^^^^^^^^^^

Siryt«rE^^^^^^^^

*cy are^redintigrated with their Whole, and wjth one another,
Wreftored to their Naturall place v in wh.ch atthe length ,
Wmg obtained their perfeaion,they fettle and rema.ne.mm^^^^^

">le. Therefore in right Motions there can be no Uniformity ,
»«r JpSy for that they vary by reafon of the uncertame
Ltvity or Grav ty of their refpeaive Bodyes : for wh.ch caufe
Sdo noVperfevere in the fame Velocity or T«Aty to the end
Whi^k u { ;n the beeinnine. Hence we fee that thofe things
lfe^.hfmak ^h thim tend downwards , do defcend at firft
moic weight roaKetn n - ^ „ approach neerer

M ' '""rThrCeLtre h y P^^^^^^^^^^ more' nd more fwiftly.

»eff ar^ carryed upwards (as this our Terreftrial Hre wh.ch is no-

twSafmUthatburneth,andismkindle^^^^^^^^

»re no fooner afcended on high, but, in almott the felf-famc mo-

■^ent, they % and vanilh outof fighti by reafon of the rare-

;»aio; and extenfion, that they as foon -^^^ue. ax^ f;«d

S thofe bonds which violently and -g«"ft jheir <>w"Na^'J

''^Pt them under, and detemcd them here below. For which
r tnem unacr, *uu Motion can be called

J=»fon, it IS very ^^PP"^"^'.' " C a hath been faid; it is not

^Plc, not only i" '^S^^^ .^i.'e k i^^^^^^

•ftoved with a Right Motion^ do 0^^^^^^^ '^nd thus

Jnt,y;wichaC.rcularMon^^^^^^^^^

' length we have evinced that r" „ J ^^^^

^mtocm and . ^quablcand of the fame tenor L ^
« IS never dcftitute of its interne Caule . «ner ^
ty, Right Motion, (which pertains^ ^ jScS^^^^^^^^^
*-»ght ) hath a Caufe that is impertett anu r^,
f4 from Dcfea it felf, and that tendeth to, and fecketh after

495

Right LMotion
helongeth to Im"
ferfeB SodicSydnd
thAt are ofti of
their natural PU^
ces.

Right iMotioft
cannot be Simflt^

Right Meti^n ii
ever mixt Wth
the CifCHlm^

Aquabilii\

* Evert]

Circular -^"^
tion is truly Sim"
pleandFerpitHdl'

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

496

QircuUr Mo-
tion ielonlttb to
the tVhalt Boi),
««i thi Right to
it t farts.

Cireulxr iDid
Sight Motion co-
i*ceiUiit, *«dmay
ct»0 togtther in
thef*mt Bod/,

fJie Earth in
j,hM '■' "^y

»h[»liitelf itjaii
tobciathilovtejt
fart of iht florid,

Tbe Authority 0/ S c r i p t u r e ^

nothing elfe but the end and terminatio^n of it felf in regav
that Crave and L-ght Bodies, when once they have attained the
proper and Natural Place, do defift from that Motion to wh.
they were incited by Levity and Gravity. Jhe'rcfore: fincc C
cular Motion is proper t.tk Whole, and R«ght Mo"on t^'^^
F<xrt^,thefe differences arc not rightly referred to Motion, i
to call one Motion Right, another Circular, as if they were
confiftent with one another : For they may be both together,
that Naturally, in the fame Body , no \fc than it .s equ >
Natural for a Man to participate of Senfe and ^^^(on,J^^ f
that thefe differences are not direaiy oppofite to one ano ^
Hereupon Reft and Immobility only are oppofed to Moao
and not one Species of Motion to another. And for the oti
differences a »;e^/>, ad medium, ^rxd area mdium, they are
ftingui(hcd„otr«%,butonly/.m.ff>, as the Point, Line aO
Superficifcs, none of which can be without the other two o
wifhout a Body. Hence it appears, that in as much as thisPfty
lofophy differs from that of Arijiotle, fo in like manner doth tn
New CofmographicalSyftem vary from the Common one, t
hath been hithertoreceived. But this by the way, »PO"°"^;,„a
ofexplainingtheFifthMaxim: For as to the truth «^ ' '
of thefc foregoing Pofitions (although 1 conceive the^"/''; .^i,,r
bable; I amrefolved to determine nothing at prclent ,
fliall 1 make any farther enquiry into them. . ... ,^^0'
The Sixth and Laft Maxim is this. Every thing is Simply ^e^.
roinatcd fuch as is in comparifon of all things, orot"
things which mak? the greater number of that kinde , but nf ^
rcfpea of a few which make but the IcfTer part of them. -J '
for inftance, a Veffel fhall riot be called abfolutely Great p^^
caufe it is fo whilft it.is compared with two or three others
it fhaU be faid to be great abfolutely, and will be lo, >
ceed in magnitude all indivials, or the greater part ot them-
again fhall a Man be faid to be abfolutely Big, becaufe he is 6^
get than a Pigmey ; nor yet abfolutely Little, becaufe klie
a Gyanc : but he Oiall be termed abfolutely Big or Little in
parilon of the ordinary Stature of the greater part of Men.
the Earth cannot abiolutcly be faid to be High or Low for tn
is found to be foinrefpea of fome fmall part of the UnivertC'
again niall it be abfolutely affirmed to be High, being con^P
to the Centre of the World, or fomc few parts of the V^^^
more near to the faid Centre, as is the S,n, MercHry o ^ j
but it (hall receive its abfolute denomination according as
be found to be in comparifon of the greater IfI"b^^ in
Spheres and Bodies of the Univerfe. Tlie Earth therci ^ .^^
comparifon of the wkole Circuit of the Eighth Sphseie w^^^^^^,,

clu(

Mai
con

iaic
Cei
the
nan
hn
(as
Inc
to]
De
fro^
toi
aiK
thh
ala
He

pyi

inr
>er
Co
tie:
Vit

Hli
JUa
hi
Wa
iff

na
G<
be
his
ic
tr<
»o

isi

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

In Philosophical CoNtaoVERSiES.

elude th all Corporeal Creatures, and in comparifon of Jupiter,
W^rj-^ and vS^^fwr// together with the Moo iiy and much more in
t comparifon of other Bodies, (if any fuch there be) above the
P* Eighth Sphere and efpecially the Empyrial Heaven, may be truly
faid to be in the loweft place of the World, and almoft in the
Centre of it j nor can it he faid to be above any of them, except
the Merr.Hvy and Ve?2us : So that one may apply unto it the
name of an Infime and Low, but not a Supreme or Middle Body.
And fo to come down from Heaven, efpecially the Empyrian,to ic
(as it is accepted in the Defcent of Chrift from Heaven to his Holy
incarnation) and from it to go up to Heaven (as in Chrift s return
to Heaven in his Glorious Afcention) is truly and properly to
'^fi/cewrtf from the Circumference to -the Centre , and to afccud
from the parts which are ncareft to the Centre of the World
to its utmoft Circumference. This Maxim therefore may eafily
*nd according to truth explain Theologicall f ropofitions : and
this is fo much the more confirmed, in that (as 1 have obferved^
^llUoft all Texts of Sacred Scripture which oppofe the Earth to
I^eaven, are moft conveniently and aptly underftood of the Em-
PyrialHeaven(being the Higheft of all the Heavens,and Spiritual
refpcft of its end J but not of the inferiour or intermediate Hea-
vens, which are a Corporeal^ and were framed for the benefit of
Corporeal Creatures: and thus when in' the Plural Number
^^cavens are mentioned, then all the Heavens promifcuoufly and
Vithout diftin&on are to be underftood, as ^vcll the Empyrian
^tfelf as the Inferiour Heavens. And this E*xpofition indeed any
^3tn (that doth but take notice of it ^ may find to be moft true.
A.nd fo for this Reafon the Third Heaveu into which St. Fanl
)^^s Wrapt up, by this Maxim may be taken for the Empyrean :
*f for the the Firft Heaven we underftand that immenfe Space of
Erratick and Moveable Bodies illumiaated by the Sun, in which
comprehended the Planets, asalfo the Earth moveable, and
^•^c Sun immoveable , Who like a King upon his Auguft Tribu-
^^1) fits with venerable Ma)efty immoveable and conftant in
Centre of all the Sphacres, and, with his Divine Bcames, doth
^puntifully exhilerate all Coeleftial Bodies that ftand in need of
^is vital Light, for which they cravingly wander about him j and
^oth liberally'and on every fide comfort and illuftrate the Thea-
^re of the whole World, and all its parts, even the very leaft, like
immortal and perpetual Lamp of high aod unfpeakable va*
xhe Second Heaven (hall be the Starry Heaven, common-
called the Eighth Sphsere, or the Firmament, wherein are all
5*^^ fixed Starrs, which according to this Opinion oiVythagoras,
^Oike as the Sun and Centre) void of all Motion, the Centre
Utnxoft Circumference mutually agreeing with each other in
Rrr tmmobility

497

Ckrifl in
Ir.cArnation trtt'
ly dejcerMd from
ll( avert y and iH
hU AfceKfioH tru-
ly afcetidcd in: 9

?. whether in tit
Ifodf or ent of th^

Sun isKin^^
He^rt and Ldmf
efthe^orld him'
[elf ^^»»/ rtt<7«pxj»t
abfoMelj indepen-

dtnt.)

Early European Books, Copyright © 201 0 ProQuest LLC.
Images reproduced by courtesy of the Royal Library, Copenhage
2°K.B. 9,163

7 be Authority 0/ Sc ri pt u

.»„«r^5«»»- Cod beinj^ the Centre of Spiritual things the bun

5«<-«»- I /-u • n. rlinfp that are Mixt, or made up ot both, tu» 6

dc Patennj
lolb.

O JVC ^sn^fuiyf ^

M.mob>Uty. Andthe Third Aiall be the Empyrean Heaven ^^^^^
s thereat of the Bkffed. And hi this manner we may con^
cxdain and underftand that admirable Secret, andprotound M
n.^.,.., 4;ni;matieally.x.vealedbyl...toP^^^^^^^^^ o^^ -(^^
FU... (-^ I AU things ar^ about the Kt»g of all things bconc

/:^£W- about the f econd, andrhird things about th^

ornnid. & Stcun-
i» citca

c"» Tm.Bm : do doubtlelle depena or iiiai. u. --- , Centre is

r,<<< Thcodo. dc r„^„j^nt and oroport bnablc to them , and the
Grxcaftea-curar. correfpondent and P^"?'"' ' , ^ier place : and therefore
lib. 2. Steuch.Ub. ever ad)udged to be the nobler and wortnier p , . f^,,

in AnimalsW Heart , in Vegitables the Pith or Kernel whe ^
the Seed lyeth that conferveth '^^eir perpetu.cy, -^^^^^^^
eludes the whole Plant, are ,n the Mtdft, - ^J^^ Centre .^^^^
thus much (hall fufHce to have hinted at, fince there may an
occafion offer it (elf for a larger E-pli""on of thefe thy_By
thisMaxim the Authorities and Arguments of the Third Four
and Fifth Clafles are refolved. „rv and

It may be added withall, that even the Snn, UercHry and |;
( th^t is to fay in refp.ea of the Earth ) • AeiS^of
ie, and not fce«c./fc the Earth it lelf although m re^ ^^^^.
theUniverfe, yea and alfo abfolutely they are Mor.. ^ ^^ove
foni=, becaufe in refpea of the Earth theyalwayes appear

• o r . ^nr^ alrhoueh they do not cnvirone it, yew 2

while another ^art of its Circumference. Since tn^etore
things which in^a Spherical Body are nearer to the CiKUm
rence and mbre rc^note from theGenrre are faid to be ab..^^ ,
thofe that are next adjoyning to the Centre are fa.d ^f^^^^^^,,
it cieariy foUoWeth that wifilft the Snn^^^^my fl^^^ ,t,c
not only turned'towards tl^ Surface and <^«^^^^P^,((^c\^
faid EaJth, butak at^ very^^feat diftance w.thou it>c<^ ^^^^^
turned al^out it, and every way have a view of it, an^
far remote from it^ (Centre, they may,.n refpefi of in
befaidtobe^ta^rif, as alfo on the other ''^e,
refpea of them may be faid to be beneath : |«>wbeit on .t^ _^
my in refpea of the Univerfe, the Earth 'V^^.^''^'^ >
they: : And thus is falved the Authority of f^^,
EccHc. . 2sl many places, expreffing thofe thing, that ^^r^'^.^der

..4 ..^fi ,1 ^ X Eeath i^thefe words,

Z ^tfAnd in the fame manner thofe words are reduced ^.

A^f'"- ,1 Senfe wherein it is faid, That we arc the
£L Moon,, whereupon Te«cnc th^gs.are ^^^"^

mmc o{ SHbliinary. i t-.i^ :» ^-ritfiiP^**

the Sixth ClaOIs threatneth a difficulty which IS eomn* ^^jj

Ma;
E

eclij
Ean
Sun
inf-
aiid
thet
tal«
plat
tot:

»CC(

fur,
upo
C,r
Of]
tot

Wit

felf,
411 f
Bod

'vlii
%

yer
fell

fori

is c

the
Pof
fine
^ r
th.

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

►at

ate
the

cry

1^^

Heaven accord*
iftg to Coper flic m
u the fame with
the mofi jentiow

1/7 r H [ L O S O P H ! C A L C N T R C V £ R S I E S. ^ ^ ^

'^cll to this of Copernicus^ as to the Vulgar Opinion , fo that they
^i"c boih alike concerned in the folution of it : But fo far as it
^Ppofcth that of Copernicus^ its anfwer is eafy from the Firft
Maxim.

But that which is added in the Fourth ClafTe^ That it follow-
^^lifrom this Opinion, that Hell (for that it is included by the
E^i'th, as is commonly held J) doth move circularly about th&
?wn, an.d in Heaven, and that fo Hell it felf will be found.to be
Heaven^ dilcover.s i^^ niy judgment, nothing but Ignorance
^^dCaUnrnv, that infinuate the belief of their Arguments - ra-
ther by a corrupt Icnfe of the Words, than, by folid Reafons
^^ken from the bofome of the Nature of things. For in this
place Heaven is no wife to be taken for Faradice, nor according
^0 the Senfe of Common Opinion, b>it (a;^ hath been faid above)
According to the Copernicaii Hyppthefis, fpr the lubtileft and
^urt'fi: Aire, far more tenuous and rare than this of ours , where-
upon the Solid Bodies of the Stars, Moon, and Earth, in their '^Xr • ^Tri/^
^i^'cular and Ordinary Motions, do pafle thorow it, (the Sphserc fnem from P^a*
Fire being by this Opinion taken away.) And as according f^feth au Z'
the Common Opinion it was no abfurdity to fay, That Hell Heavens.
'^^injrdem'j.r^cd in the Centre of the Earth and of the World it
^clfjhath Heaven and Faradice above and below it, yea and on,
^11 fides of it, and that it is in the middle of all the Coelefiial
Bodies, (as if it were poficed in a more unworthy place^ fo, nei-
^Wr in this will it be deemed an Ertor, if from the other Syftem,
Hich dilFerech not much from the Vulgar one, thofe or the like
:^^gs follow as do in that. For both in that of Copermcm, and
Vulgar HypocheiiSjHell is fuppoled to be placed amongft the
:J^^y, drcggs of the^Elements, and in the Centre of the Earth it
pf> for the confinement and punjflbment of the damned. There-
We ought not ifor want of Reafons to trifle away time in
: and in>pertinait ftrife about ^^W^^ fi"^^ their true Senfe
clouded then wichiio pbfcurityy and in regard that it is very
[^^^1' to any man indued with a refined Intellcft, and that hath
;^^.^'^n indifferent judgment in the Liberal Arts, and efpecially
f ^he Mathcmaticks, that the fame, (Or not very different Con-
^yences do flow from i3oth thefe Opinions.
. % thefe Maxima, and Interpretations it appears , that

^^^fyihagorUk^giiii^^^ is fo probable, that its

f^ffible itr iiiay cxceed cvcn the ?tolemajcl^ in probability j and
^^^ce there may be.deduced from ii.a moft ordinate Syfteme, and
\%oe admirable ^ and myfterious, liypothcfis of the World
^^^^ from that of ?t bh^y : the . Authorities of Sacred Scripture
theological Tenents iu the mean while not pppofingit, be-
opportunely and ^BppfitelyfC^I l^h.av.e.ffiQWn how they may
R r r 2 \}c)

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

(a; Exod.a5.5i.

(b)M/ Aftthoftr
fillow'tng theval'
gar Tmnfltuon ,
vhich hath an £-
Usance in fome
things Beyond oitrs^
cites the vfords
r«!s;r,Facics Can-
dclabrnm dudi-
Icde aaromun-
dilFimj, Haftile
ejas,& Calamos,
& ^phxrulas, ac
Lilia,cxipCoprc^
ccdcntia.

(d) or Spheres-
it) ThoMgh

A^thour fpe^'^^
here pofiiively
tttne Months
Esthers ttre not a*
greed sboHt the fe-
rndofthis pLtnet-f
mrthatofWxcM'
ty^as joH may fee
at Urge inKxcCiO-
lu$,Mrragelt.nov.
Tem. I. fart 1.
'j,fe[t.3. cha. ii»
num,i t'paged^J-
vrhere he makjth
Venus toconfunt'
mate her Ke'vo^f*'
tion in neer 225
iiijes^9r 7 -J Mon^
Andyi-^oxw^ in <*-
boat 83 dayes^or 5
Jl,/OMths ' in which
It jolloxveth K-pl.

Afiro-

The Authority of S c r i p t u a e,

be ) reconciled with it : And fince that by it not only
nomenaofall the Coeieftial Bodies are moft readily lalved, but
alfo many Natural Reafons are difcovercd, which could not o-
therwile, but with extrcam difficulty) have been found out-
And fince it, laft of all, doth open a moreealy way into Mtro-
xiomy and Phylofophy, and rejcaeth all thofe fuperfluous an
imaginary inventions produced by Aftronomers to the end only?
that they might be able by them to render a reafon of the lo ma-
ny and fo various Motions of the Coeleftial Orbs.

And who knows,but that in that admirable compofurc ot tn
Candleftick which was to be placed in the Tabernacle of God,ne
might out of his extraordinary love to us have been plealeo to
fliaddow forth unto us the Syfteme of the Univerfe, and mor^
efpccially of the Planets? {a) ^honjhalt mal^c a CandleftlcKp
fnre Gold, ( faith the Text ; ) of beaten wor^Jhall it be tnadf^
his Shaft-, and his Branches , his Bowls , his Knops, and
Flower sib)fhall be of the fame. Here are five things defcribed,tn^
Shaft ofthe Candleftick in the midlc, the Branches on thefide«>
the Bowls, the Knops and the Flowers. And fince there can be
more Shafts but one, the Branches are immcdiatly defcribed ii^
thefe (^c ) words : Six Branches fhall come out of the fides of / •
three Branches out of the one ftde^ and three Branches out of ^
other fide : Happly thefe fix Branches may point out to us
C(i)Heavens,which arc moved about the Sun in this orderjS^^^'' '
the fiowcfl: and moft remote of all, finiftiethhis courfe about tn
Sun thorrow all the twelve Signes of the Zodiack in thirty ^c^^^'
Jupiter^ being nearer than he, in twelve Years : Mars., being
nearer than him, in two Years : The Earthy which is ftill nearef
than he , doth perform the fame Revolution , together witn
the Orbc of the Moon^ in the fpace of a Year, that is in Twelve
Months : Venm.yNhich is yet nearer than all .thefe,in(0?^^^ 1'
And laft of all Mercury, whofe vicinity to the Sun is the gr^^^^
of all, accomplifheth its whole converfion about the Sun in ^'8"^^
Dayes. After the defcription of the fix Branches , the lacte^
Text proceeds to the defcription of the Bowls, the Knops, an
the Flowers, faying , (f) Three Bowls made like unto Almott(^^j^
with a Knop and a Flower in one Branch s and three Bowls ^
like Almonds in the other BranchyWith a Knop and a Flower ''J^
fhall be the work of the fix Branches that come oHt oftheSi^^J'
And in the Candleftick^ fb all be fonr Bowls made //% ^^^^ ^
monds^ with their Knops and their Flowers : there fhall be ^ ^^ J^
under two branches of the fame, and a Knop under two 3ra^^ -^^^^
ofthefamey and a Knop under two Branches of the fame i ^'-^^^j^
titgether are fix Branches, proceeding from one Shaft, The tt\x^^^
is> the (hallowneiTe of my undcrftanding cannot f^^^^^j^ ^f,

eti>

/^Philosophical Controversies.

depth of ail the Myftcries that arc couched^ ia '^1^'"'^^ ^^"^
difpolure of things : neverthelelTe being amazed, and tranfported
wicLdnVK tion,! will fay i Who kno-^ut that hole three

Bowls li/ce unt'o Almonds to be -P-f^i^^^^" "^hkh are
Branches of the Candleftick rnay fignihe thofe globes which are
apterfas is this our Earth)for the receiving than em ttitig ot InHu-
en f pe haps alio they denote thofe Globes of late d.lcovered
by L he p of the Opik Telefcope , which participate with
slZ 7„L r F.»;^, andpoffibly alfo with the Other Planets ?
xCL^wriikewifcit that there may be lomc occult propor-
tio b twee thefe Globes and thofe Myfterious Knops and
Lilies infuuuted ur^to us in the facred Scr.ptures ^ But th.
fliall here faffice to bound humane Prefumptton, and to teach us

on one liand and five on another, in the Temple eredted by mm

inrn:;;r:^tUoftmghGod.w^^^^^^^^

.ithont all J" t ^fCCw ed of toS Evil prohibited
::rkS^et by S notwiLutaMyftery ; which Tome
? /n lnSigg. In which thefe things are to be obferv-
/"^Firft Thatif repletewithmany Kernels, every one of
whichSa particular c'entre. Secondly,
V hard and folid, yet about its Circumference it is of a more rare
and tenuoufe fubftance herein refen^bling ^bc Earth which
though in its Centre, and thofe parts which are neareft to « t

'^^Vteamc Reprefentation withthatof the Indian Figgis heW

forlh^o r by'the M./.».F'^«--> ^ J^STn^re pans

WumerablepolycentrickStonesorKern^^^^^^

".ore remote from their Centre and nearer app^o g

the CircuiT.ference,are of a fubftance fofubtU and r^^^^^

but lightly compreflcd, they '^-Xh fru' yeafed Divine
mofttenuofe Liquor or jmce : ™ 'pfg^ire
M'ifdom to make\nention, and -^^In JetS^
>r.broideredandwroughtw.than^^^^^

Aaron: (h) Beneath {iitthCod ) 77/*' , ^nAoffrtrht 34. « 5

^OHtid about the l?order thereof , ana dcutJ j ^ ^^^^^

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

(h) Joel C. I.V.I 2

W Hagg. c

Tjol 7^^^ Jntbority O0 c r i p t u k s

round tibont : a golden bell and afqwcgranate^n golden b'^U ^f^^^^
pomegranate^ upon the hem of the Kobe round about. And that
was a Myftical Reprelentation of the Worlds Effigies, is averrc
(0 V ^. ^8. V. by Solomon, fayingi (i ) For in the long ( h^) Garment that e
\\)Exod c i^^d on wa^ the{iyvhoU World; andzn the fonre rows of thejio^^
^.6,9.17.16. was the Glory of the .Fathers graven, and thy Majejiy in the
(OOr^fotusOr ^^^,,,,fhi,Head, ^ .

Z wWrTlni- The fame likewife is fignified to us by the Crape, and m hkc
ladon hath it. manner by all other Fruits , but cfpecially the l^gg, Grape, an
Pomegranate: whence thefe three are almoft alwayes placed fo-
geriicr in the Sacred Scriptures. - So Numb, ao. the People ot m\
el complain againft Mojes and Aaron : (w) li herefore have)0
Numb.c.io. ^^^^^ ^ ^^^^ ^^^j Egypt, to bring lis into this evil pU^^^
where there can grow no Seed , ?ieither is there either Figgs,^^
Vines^ or ?omegrandtes ? • Intimating that tliefe kinds of Fruits
were preferred by them for tjieir excellency before all others-
And in Joel («) the Vine fs dryed up, and the Figg-trce hnguifi'
eth.the Fomegranatc-trce. the Falm^trce alfo^jnd the Jpple-tree,
even all the Trees of the field are withered; becaufe joy- rs wiih^^'
MHao^ c 2 cdan^ayfrom.theM^'sofMcrt. Likewife in F^^^z ; (o) Is t^J
V.19. ' feed yn in the Bud} and bath as jet the Vm^tid t

and th§ Pomegranate, and tl^e Olive-tree broHght forth} ^^^^^
n\zmcf:M\ DeHteronomie the Land ofPromife is commenoe .
(rtDcut.c.s.v.8. h^(p:)d Land of meat, ^ndBar^^ ^¥\^£tlie
Vigg'treesy and Pomegranates, and Olivc.-trees., &:c. And in n ^
Stiuau^e of th^ TemiiLe ui)flertaken by. Solonm upmjp.jyiP^ '^'
{q) 1 Kii'e'^c 7. fpiration 1lhe(^> GHapi,ters of die Pillars were adorned with. frX^"
V.20. & i Kiii-s j-^ij-Q^v^srof . Pomegranates which particular js mentioned^ ^^^^
tcL'^.^v.if, inonehucWny^pk^efiofHoly^iit, Yea ;^nd fomcdjnes^ac^-
^- • deritalW- and occalioilftlly tli^ HpJy hath Ghpft • xnignianfajly
prcfented 'ChiS'moft adniirable ^i;^ Wife Sruaui^ot
VVijrld, ihc.Order of the Heavens, and the dilpofure f ^^^^
tures Spiritual and Corporeal by Embletm, Parables, and F»g^ ^
leafi they, fliould be as it weredazled and blinded, by the leta J
geiicffplendoroffo excellent aa Objca-. Hence we lee, that i^
thefe Doftrinal Sc Dubious Points we may difcourfe in fuch nian
mr> bv help of the Holy Scripture as is meet for the "i^^^^.^^^^.^^
of the Prophets-, which feeing they are very obfcurcthey (haJl
fully underftood, and may be aptly applyed only then when t^j^
ftall be fnlhlled, and not before : So alfo when once the t^^^
Syfteme of the Uiiiverle is found out, then, and not til theiv
meaning of thefe Figures, and Enigma's fliall be n^ade. P
unto US : Thus befpre the coming of the Son of God .had,"i
ver<!d unto us the Myftery of the Holy Trinity, nofte ^^^^.^^J^^^
to comprehend ot imagine what was concealed "n^^^v^,^^^^

1 3. & Jertm

^2,V. 21

r H f L O S O P H

icAL Controversies.

Words-, (r) In Friiicipio cn-^vil Elohim Cxlum df^ Terram : for (OG^" ci.v.i.
lhatthey did not tee how the Noun PkiraI£/o/ji»*(which is as much
as to lay Dij, [Gods] (hoiild be joyned with the Verb Sing

^reavit : But the Myilery ot the Unity of ElTence and Trinity
of Perioiis in God being revealed, it was prclently known, that
k Sinaular Number, Crca-vit, had reference to the Unity of Ef-

K fence ,''(in regard that the Works of the Trinity ad extra arc in-
I divifible) and'the Plural, Elohim, to the Perfons. Who, I pray,
I in elder times could have found out this Myftery ? And thus the
^fc. Name of God is thrice repeated in Pfal. 67. (s) Cod e'-^cn our
^MGoftfi.HMcf- :0, God Ihall bleffc m, &c. Which at firfl might
^'feema Plconafme, and llipcrfluous repetition •, but afterwards it
■ Was evident thic P^w^/ did there fct out the Benediaions of le-
I Veral Perlons implyed, to wit, the Father, Son, and Holy Ghoft.
r rnhuTrcfa^lc Examples of the like kind may be found m t^ie Sa-
cred Leaves. Therefore, to conclude, I will fay with
^Mpa Oh Lord how glorious are thy Work/! thy thoughts
^ft'verydeef: an mwijematt knoweth'not, and a fool doth not
'ittderliandthefe things. , , r a-

Thefe are the particulars that I have thought to offer , as
a Divine, concerning the not-improbable Opinion of the Mobili-
ty of the Earth and^Stabiiity of the San : which I hopc^will be
acceptable to you, Reverend Sir, out of the love and diligence
Wherewith you pcrfac Virtue andLearnmg. But (to the end
that you may alfo receive an account of my other Studies^ I
Jiope very fliortly to publifli in Print my Second Tome *0f the In-
flitHtioiis of all Learnings, which (hall containc all the Liberall
Arts, as I have already fignificd in that Syntax, and Spicimen by
'ne heretofore put forth, and publiflied under your Name. The
*»tlier five following Tomes by me protnifed (which fhall treat of
Piylofophy and Theology) arc not altogether fo forward, ne-
IL ^"theleE they will be fpeedily finifhcd. In the mean time there
i ^viU coi„e forth my Book Concerning " ©racles, now fimlhed to-
I gethcc with a Treatife ' Of Artificial Dt<v,nation. And for a
I pledge thereof, I fend y ou at this time annexed to this EpiUlc a
i Tral » Conccrntng NaturalCofmological Di-vinanon, or of Natu-
^ ^=^1 Prognoflicks, and Prefages of the Changes of Weather and
«ther things which fall within the compaffe ot Natue. Cod grant

you all HappincfTe.

" -Uofi HeverendSir

Naples , from the Covent
of the Canmlitcs, Jan. ''"'^'^'J^ "^'"^'^

^' PAOLO Al^romo FOSCAKlNl

(0 Phi 6 J.

-y

(

FINIS,

* Pfal. 91 v.5/n

* InfiitMthnum
omnium Vottri^

* DeDivinatiffi
ne artificiofa^

« Be VivimUio'

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

TABLE

Of the moft Obfervable

PERSONS and MATTERS

Mentioned in the F i ^ s t P a r t of

The Firft Tome.

Ab S T A C T.

T Kings are cxadly the fame m A^Bta^, as
, in^Concrete.

AiR£-

The part of the ^/V^ infcriour to the Higher
Mountains doth follow the Motion of the
Earth

The motion of the v^/V<f apt to carry with it
light things, but not heavy. / J 24

I'he ^ire alwayes touching us witlv.thc lame
part of it, cannot make us fed it*

*t is more reafonable that the Aire be comniovcd
by the rugged furface of t he Earth , than by
the Celeftial Motion. 40£>

" is demonftrated , inverting the Argument,
that the perpetual Motion of the Jiretvom
Eaft to Weft , commeth from 'the Motion
of Heaven. 4^3
Animals.
P'ide, The Motion of u^nimafi:

"^hc caufe of the WcariucfTc that attends the
Motion of Animals. -44

Apollonius*
'^polhnim and Copernicus demonftrate the

irogradations of Venus and Mercury. A 311
Arguing, A rgHmentS:Sc ArgmicnUtions
Arguing fix in their minds chc. Cpnclu-
^^on believed by them 5 and then adapt. thvir
^eafons tothat. ; ^ ^5^

One

One finglc Experiment or found D cmbhdrati-
on , overthrowcth all Arguments raeerly pro-
bable. 165

A pleafant Example fhewing the invalidity of
fome Phifical ArgmentAtions, 3^5
Ar X S.T A R C HUs.

Rcafon and Difcourfe in Ariflarclm and Goper-
; nicus prevailed over manifeftSenfci 301

A I s T o T L t .

Ari^otle raaketh the World perfe^ , becaufeic
hath the Threefold Dimenfion. *

Arift* his Demonftrations to prove the Worlds
Dimenfions to be three, and no more. %

^r/)?of/<? his Definition of Nature cither imper-
fc($l or unfcafopable. 7

y^ri(/?^?r/<f accomodates the Rules of Architedure
to the Frame of the World, and not the
Frameto the Rules. S

^W^i7^/(3 cannot equivocate^ being the Inventer
of Logick. ,; .„. . •'• . : 25

ArifwtU his Paralogilme in praving.. the Eartn
to be in the centre of the World, " 24

><fr//r.Paralo2irme another way difcovered. 24

Arifloile his bilcouffc to prove the Incorrupti-
bility of Heaven. - ,• - 2^

^r/7/cr/^proveththat Circular Motion hath no
Contrary. , . 2^

Ariftotle detcaive in aflTgning the Caufes, why
•the Elements aye Gencrable and Corrup-
tible.. , ■ ■ ... - 31

Ariftotle would change his opiaiopj d^?* tee
the Novelties of our Age, . ^^J

» - [Hrt]

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

The Table.

Arifi. prefen-es SenCe before Ratiocination. 42
^/^^/^affirmeththe Heavens alterable, rather
then otherwife, by his Doarine. 4*
Requifites to fit a man to Philofophate well in

ihcvjayo^Anflotle. 9*
Someot AriptUs Seaators impaire his Repu-
tation 5 in going about to cnhanfc it. 9 3
Thefervile Spirit offome oiArtft. followers. 9 5
Too clofe an adherence to /riitotU is blanac-

able. ^5
AMeand Vtolomy argue againft the Diurnal

Motion afcribed to the Earth. 91
A Propofition that Arifiode filched from the

Ancients, and fomewhat altered. ^ ?^
AriM^ his Arguments for the Earths Quie-

fcence and Immobility.

were he alive , would either r Jte his

Adverfarics Arguments , or elfe would alter

his Opinion. . ^ , -VJ

AriHotUs^t^ Argumentagainft theEarthsMo-

tion, is defeaiacin two things. ^ 121
The Paralogifme of ArmUznd Ptolomy m

fuppoiing thatforknown, which is inque-

^r!^w/^'admitteththat the Fire movethdirea-
ly upwards by Nature , and round about^Dy

A^m!^^^^ feem to confute theEarths
Mobility asainft thofe who think that it, ha-
ving alongtimeftood ftiU, began to move in
the lime of Pythagoras. *^
Armotle his crrour in affirming falling Orave
Bodies to move according to the proportion
.-1 • ,«:«.;a>c

" • * t99

ASSth that point to bethc Cent,^^^^
the Vniverfc , about which all the Celeftial
Sphercsdo revolve

Aqueftionis put,if.<r^/?. were forced to receive
one of two Propofitions , that make agamlt
hisDoarine, which he would admit. a^4

Armotle his Argument againft the Ancients,
who held thattheEarth was aPlanet 344

AriB^tle taxeth Plato of being over-ftudious ot

.frSlTholdeththofeEffeastobe miraculous,
of which the Caufes arc unknown. 3«4

Astronomers.

Aflronomtrs confuted by Anti-Tycho- 3^
The principal Scope of Astronomers is to give
a teafon of Appearances and Phenomena. 308
AHfonomers uU agt^e that the greater Mgni-

tudesof theOrbes Is the caufeof ihetardity
in their Converfions. 33 '

t/ffironomers perhaps have not known what
Appearances ought to follow, upon the An-
nual Motion of the Earth, 33|^

A^ro«(7»*^r/ having omitted to inftancc what al-
terations thofe are , that may be ^^nvea
from the Annual Motion of the Earth 5<^o
thereby tcftifie that they never rightly un- -
derftoodthefamc. 34?

Astronomical.

Ajlronomical Obfervations wreftedby Anti-Ty-
cho to his own purpofe. 3^

Mronontiical Inftruments ire very fubjed
crrour.

Astronomy.

Pifironomy reftored by Copernicus upon the
Suppofitions of Ptolomy 3^^

Many things may remain as yet unobferved in
hftfononrf

AUCUPATORIAN*

An AucM^atorian Problem for footing of ^^^^^^
Byingo

AxioME, ot Axiomes*

Inthe Axhmey Fru/lrafi perflura.d'c. the addi-
tion of aqu<e hene is fuper fluous. *
Three Ax/<wj^/ that arc fuppofedmanifeft. *3|j
Certain Axhmes commonly admitted by ^1»
Philofophers. 3<^*

Body and Boditt-

Contraries that corrupt , rcfidenotinthcfaffle

perforated, a Gn^e Bodj> defceriding by u^j
Bore, would pafle and afcendas farbeyon
the Centre , as it did defcend.
The motion of Gr<M Bodle,, Vide J>^<,th»' ,
The Accellerationof Cwi-* BodJet that do^
naturally , increateth from momcn'^^j
moment. Bodies
We know no more who moveth <^rave
downwards, than who moveth .^^
round ; nor^kpow we any 'thing ^ga^ks

the Table.

06
30

all
61

ere
bat

oJ
//^/
ars
efc

Courfes, more than the Names impofcd on
ihem byourfdves. . , .

the ercat Maffe of Grave Bodies being tnni-
ferred out of their Place, the feperated parts
would follow that MalTe.

t>B N s 1 L E B o D Y ; Every B.^ earned
round in the Circumference of a C ircle , ac-
(^uireth of it felf a Motion in it felf contra^ry

to the fame. „AZ
Celestial Bodibs neither hcavy nor

lisht according to JriPotle. 3
Celepial Bodies ^S: Generableand Corruptible
becaufethey are Ingenerable aud Incorrup-

liblc. .
Amonpft CeleL Bodies there is no contraricty.19
mial Bodies touch At are not touched by the

Elements. , jicc

Rarity and Denfity InCeleffiat Bodies , different
from Rarity and Denfity in the Elements. 3 0
Olejlial Bodies dcd^ncd to ferve the Earth, need
no more but Motion and Light. 45>
Bodies wantan interchangeable Opera-
tion Un each other. ^4
Oij?S2laIcerabieio their eKtern^^^^^^^^
Pe/fcdl Sphericity whyafcr.bedtoC<fe//4/y^

^onrofoYo^tLLth^hath^limitedSp)^^^^

of A^vity. , J t. '

IxoHT Bodies cafict to be moved than heavy,

but leffeapt to conferve the Motion. 400
lu M I N o u s B 0 p 1 1 * ; B»f ^naturally I«.

».««.«, are different from thofe thatareby na-
^tureObfcure. . 34

Thereafonwhy iMmiumSttUu 3.ppe3xlomwb

themoreenlareed, by how muchthey arc

leffcr. L
Manifeft Experience (hews ttet the more r^^^^

B<,<A-rdo muchmoreirradiate thanthe

Sx^h""Bo»v.s have but one Simple
, Motion that agreeth with them. W

J^orySm is the Centre, and5»r/««. the C.r-
fcteivce. '^'f

Bones.

The ends of the jow/ are rotund, and why. sji

BUONARRUOTTI.

^""^rmtti a Statuary of admirabk ingenuity.

C A-

C A N O

A Qiameful Errour in the Argument taken from
the C4««»-BuUets falling from the Moons
Concave. ^^7

An exaa Computation of the fall of the Qtnon-
Bullet from the Moons Concave , i6 the
Centre of the Earth. ip8

Celestial

Celejli^il Subftanccs that be Unalterable , and
Elementary that be Alterable, neceffaryttt
the opinion of ArifletU, »

C E N T R *.

The Sun more probably in the C^^^r^ of the V-
niverfe , than the Earth. 2 a

Natural inclination of all the Globes of the
World to go to their Centre, 2 %

Grave Bodies may more rationally be affirmed
to tend towards the ai^r^ of the Earth, than
of theVniverfe. 25:

C H Y M I s T s.

C*;w//r/ interpret the Fables of Poetsto be Sc«
crcts for makingof Gold, ^5.

Clrcle, and Cirr«l^r-

It is not impoffible with the Circumference of i
fmall C/Vtf/<! few times revolved, tomeafurc
and defcribe aline bigger than any great C/r-
cle whatfoever.

The Circular Line perfect, according to Arifmle^
and the Right imperfect, and why. 0.

Claramontius.

TheParalogifmeofC/;iM«^>;i//«^. ^ ■ 241;
The Argument CUramontii^i recoileth ui)ort

himfeif. , . .

The Method oWerved by eUramonuuf incontu-
tiitg Atonomers, and by Salviatus in re-
futing him. *5 J

Clouds.

Clouds no Icffe apt than the Moon to be iUumi-
naccdbytheSun. 75

The Tahk

CoNCLUSioi^^nd Conchfions.

The certainty of the Conclufton helpcth by a refo-
Uuive Method to findc the Demonflration.37

The Book of frequently mentioned,

was writ by Chriaophcr Schciner a Jcluit.

Coi^TRARlES.

Ccntranes that corrupt , rcfidenot in the fame
Body that corrupteth. 3^

Cop ERNI CAN*

Anfwers to the three firft Objeaionsagainftjhe

7hc Copm.icr. S)Jlem dif^icul to bcunderftood,
buteafictobeefleaed. .354

A plain Scheme reprefentingthe Coptrmcan Sy
fleme and its confequences. 354

Theprofcribingof the CofernicM Dodtrine , at-
terfo longa Tolleration, and now that it is
more than ever fodlowcd , ftudied and con-
firmed , would be an affront to Truth. ^444

^hzccpcrn. Syftem admirably agreeth with the
Miracle of ^-o^uah in the Literal Senle. 45 6

If Divines would admit of.thc Copemcan Sy-
ftem,they mightfoonfind outExpofitions for
all Scriptures that fccm'tOffcnake againft it.4 jp

The Cofernican Syftemrejcacdby njany^outota
dc^'OUtrefpetltoScripiurc Authorities. 461

-Chc CoPtrnican Syftem more plainiy tiflcrtcdin
Scripture than the Piolomaick. 4^9

"' ■ i

Cover n 5 c a
• • - ' "
CoptYfjianf \xQ not moved through ignorance of

the Ai^ttmcnts onr^the A'dveri.crpa^t. 1 10
CcpernianfyNtxc all firft again ft tharOpiQion,

but thi: Peripateticks were never on the

other fide. • T" ^ .^

CopemU^ns too freely admit certain Propofiti-

6ns for true, whichare doubtful. 15P
Hethatwili ht^Copermcan muft deny his Sen-

fes. ^ , .

A Great Mathematician made a coper mean ^ oy
looking into that Dodlrinc , with a purpofc
to confute it. 443

0/^«V«.hls Opinion overthrows the Crlterim
ASoKtt[n\heOppo(e.cfJ^^^^^^^^

C.,^St opponent h.d but

him,as appears by another grofle E«our 2 5
Its queftione'd whither he underftood the th.ra
Motionaffignedto the Earth by C^fern.^^
C./«;V«.erroneouny aflignesthe fame Opera

tions to different ...
Adcclaration of theimprobabihtyof C"/^'*'^"
Jqis Opinion. . j A,:fjir-

Reafon and Difcourfe in Of emeus and Anit.^ ^
chus prevailed over Senle. ,..,An.
C«/«m«s(peaketh nothijfof the fmall Varian
on of BigncfTc in Venus and Mars. J"
CoptrmcHt pcrfwaded by Rcafons contrary
SenliblcExptriments. 3
Copernicus rettored Aflrononiy upotuhe SopP^^

fitions of Ptoloniy. \
What tuovcd Cofmim to eftabhlh his Sy^

Its aTreat araumcntin favour of CoftrnicutM^
^ Kviat?s the Stations and RetrogradaU
> onsofthe Motions ofthe Planets^ ?^/^
Inftances Ironically propounded by

' -ioam&Cepermius. „r for want

atfrnicunMcod. not fomethingstor w

is that which concerns the Phenomena
the Sunand fixed Stars. ,
CMusxh^ Reftorer of the Pythagorean Hy
.-pothefis.andthcOccafionofit.
cJernims founded not his Doarine on Rea^"
: 'depending on Scripture --l^^^^ll^fl
' have niiftaken their Senfe, but upon ^ ,
" ral Conclufions and Mronotnica' an ^
omctrical Demonftrations;

the perfcaion of Figure operates in CompU^^

Bodies , but not in Eterna .
The Difparagers o^ CorrupM^ty ought

turned into Statua's. _ (o doth

Orr«;r/^////)admitsofmorcandle{re, lo

not Incorruptibility'

Councils.

Obieaions of two Modcmc Authours [Schci- P i a-

ner and Claramontlusl againft ^^/^/^^^'''^^^^^^

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

The Tahk.

^i^monds ground to divers fides, and Why , 63

DiDACir|.

mAcns a Stunlca reconcilcth Texts of Scripture
withtheCopernicanHypothcfis. 46^^

V Definitions.

^fnitlons contain virtually all the Paffions of
^ the things defined, ^7

Earth.

^ Thc£4r/i& Spherical by the Confpiration of its
, parts to 20 to its Centre. .u.«^w
feis eafier to prove the "Earth to move, than that
^Corruptibility is made by Contraries. ^7
The £4r^lvery Noble, by reafon of theMu-
^ rations made therein* i^irn^fl^ ,

The E^rth unprofitable and full of Idkncfle ,
its Alterations being taken away . 45
the £4rr/^ more Noble than Gold an^i Jewels.

TheCeleftial Bodies dcfigned to ferve the Urtk
^ Reed no more but Motion and Li^ht. . 45
The Generations and Mutations that arei^ntnc
£4rr;^, are all for the Good of Man. 47
from the Unh we lee more than halt the Lu-

SeSetmblances between the Mrthjn^
Mo n ^ ^055

Jhe ^rf* unable to reflect the SunsKays. 5ft
^hc i,rth may reciprocally operate on Celefti
. al Bodies with its Light,
Affinity between the f^r'* and Moon, by re^a^

t&SSo7ttfI:«^in>pe-^^^^^^^

the have no other Motions than
thofe which to us appear commune to all the

^ reft of the Vnivcrfe , the tarih excepted. 91

ll)e Diurnal Motion feemeth commune to a»
t\\c Univcrfc , the tanh onely excepted. 97

Ariftotle and Ptolonv argue againft the E4r(W/
liintnal Motion.

The Diurnal Motion of thcEa^fc. Vide p/ar-

C^^entsto prove the DtoalMc^i-

on to beloncr to the Earth, 99 to i®5

The Earth a pencJent Body , and equilibrated
' in a fluid Medium, fecmsunablcto refill the

Rapture of the Diurnal Motion. 103
Two kinds of Arguments againft the Earth

Motion. ' ■ t

Arguments of Ariftotle, ptolomy, Tycho, and
other perfons , ao:ainft the Earths Motion*
^ 107&10S
The firA Argument againft the Earths Motion
taken from Grave Bodies falling from on
high to the Ground. . r i ^

Which Argument is confirmed by the. Experi-
ment of a Body let fall from the Round-top
of aShipsMaft. ' , .

The fecond Argument, taken from a Projedi

(hot very high. . . cu

The third Argument taken from the Shot ot a
Canon towards the Eaft, and towards the
Weft.

This Argument is confirmed by two Shots to-
wards the North and South , and two others
towards the Eaft and Weft. .icq
Theifourth Argument taken from the Clouds
and from Birds. , ^ -.vrw-'y V}'
A fifth Argument taken from the Aire^ which
we feci beat upon us when we run an Horfe
atfullfpeed.
Afixth Argument taken from the whirlmg ot
Circular Bodies, which hath a faculty to
extrude and difiipatc. 1^4
The Anfwer to Ariftotlesfirft Argument. 1 15
The Anfwer to the fecond Argument. 1 1 7
The Anfwer to the third Argument. 120 to 15 0
An Inftanceof the Diurnal Motion of the iizjrf/^,
taken from the Shot of a Piece of Ordinance
perpendicularly , and the Anfwers to the
fame, (hewing the Equivoke. 1535^54
The Anfwer to the Argument of the Shots of
Canons made towards the North and
South.

The Anfwer to the Argument taken from
the Shots at point blank towards the Ealt
and Weft ^'^^
The" Anfwer to the Argument of the flying
of Birds contrary to the Motion of the

An Experiment by which alone is Ihcwn the
Nullity of all the Arguments produced a-
gainft the Motion of the Earth, 16$
The Stupidity of (ome that think the Eiirth be-
gan to move., when Pythagoras began to at-
fiimc thatitdidfo.
Pi Geometrical Demonftration to prove tnc
Impoffibility of Extrufion , by means ot
Ihe earths Vertigo 5 in Anfwer to the bm

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

He Table.

Argument.

Granting the Diurnal Vertigo of the 'Eartp , mm
that by ferae fuddcn Stop or Obftacic it were
Arretted , Houfcs, Mountains thcmfelveSj
and perhaps the whole Globe , would be
fhaken in pieces. . ^9°

Other Arguments of two Modern Authours
[Scbciner and. Claramontius ] againft the
Copernican Hypothcfis of the Earths Mo-
tion. 195

The firft Obje(5tion of the Modern Authoor
[Scheincr] inhisBookofConclufions. 195

The Argument of [Claramontius] againft the
earths Motion, taken horn things falling per-
pendicularly, another way anfwcrcd. 223

The Sarths Motion colleded from the Stiars.

229

Argumeuts againft the £jrr^/ Motion , taken
ex rerum natura.

A Simple Body as the Earth , cannot move with
three fcvcral Motions. ' 23^

The Earth cannot move with any of the Moti-
ons affigncd it by Copernicus. 231

Anfwers to the Arguments againft the £arths
Motion 5 token *x renm n <itnrA. 231

Four Axiomes againft the Motion ^of the £'^r//;.

236^0232

One onely Principle might caufe a Plurality of
Motions in the £<?rM. ''^.33

The fame Argument againft the Plurality of
Motions in the Earth , anfwercd by Exam-
ples of the like Motions in other Celellial
Bodies. ' ^' 136

A fourth Argument [of ClaramontiusJ agamft
the Copernican Hypothefis of ihc Earths
Mobility. ^ ^39

FromtheE4rr^Jobfcurity 3 and the fplcndorof
the fixed Stars, it is argued that it is move-
able, and they immoveable. ' " 2-39

A fifth Argument [of Claramontius] againft
the Copernican Hypothefis of the Earths
Mobility. * 240

Another difference between the Earth and Ge-
Icftial Bodies , taken from Purity and im-
purity. 240

Itfeems aSolecifme ^ to affirme that the Earth
is not in Heaven. 241

Granting to the Eanh the Annual , it muft of
neceffity alfo have the Diurnal Motion affi-
gnedtoit. 300

Diicourles more than childifti , that fervcto
keep Fools in the Opinion of the£4rfAy Sta-
bility* ' 301

The Difficulties removed that arife from the
moving about the Sun, notfolitari-
Iv , but in confort with the Moon. 3^7
^ ' ' The

76 The Axis of the Eanh continueth alwaycs pa-

kdpfcribeth a Cylindrai-
cal Superficies , inclining to the Orb. 344
The Orb of the Earth never inclineth, but is
immutably the fiime. 34^
The £artk approachetji or reccdetb from the
iExed Stars of the Ecliptick the quantity ot
the Grand Orb. 34^
If in the fixed Scafeone fhould dikoverany Mu-
tation, the Motion pf the Ei?r;-^ wrf^
undeniable. • • - r ' < -fi- ^^-^
Ncceffary Propofitions for the better concei-
ving of the Confcqu^ncx^ of th^farthsMO"
tion.

i^n ^d jTfiirable Accident depending on tl]?'.^^^
inclining of the Earth Axis. ; , .3^^

Four feveral Motions alTigned to the Earth,

The third Motion afcribed to tht Earth 9 is ra-
ther a refting immoveable. 3^3

An admirable mterne vertue [or faculty] of
Earths Globe , to behold alwaycs the {^^^
part oi Heaven. , l^i

Nature, as iu fport , maketh the E'bbing ai^*^
Flowing of the Sea to prove the Earths

^' tility: ^ ' ' V9

AH Terrene Efft^s indifferently confirm the
Motion or Reft of the eJtceptthe Eb-
bing and Flowing of the Sea. 3^^

The Cavities of the Earth cannot approach Of
recede fron:i the Centre of the fame. 3^'

The Hypothefis of the Earths ^fobility taken
infivour of the Ebbing and Flowing^ oy:
pofbd. " ' .

TheAnfwerstothofe Objeftions madcag^^^^-
ihe Earths Motion. $99

The R^evplution of the Earth confirmed by 4
' new Argument taken from the Aire. 4^^

The vaporous parts of the Earth partake of its
Motions. 4°^

Another obfervation taken from the Ayr, 1?
confirmation of the motion of the Earth, 40^

AReafon of the continual Motion of the Aj^
and Water may be given by making tn?
Earth moveable, rather then by making
immoveable. ^'?r

The Earth's Mobility held by fundry g^catPni^
lofophersamongft the Antients. ^37^^ g

The Fathers agree not in expounding theText
of Scripture that are alledged again/t tn
E4r;^i Mobility.

The Earth Mobility defended by many ^'
mongftthe Modern Writers. <v r

The Earth ftiall ftand ftill after the P^y ^
Judgement. 4^^

The Earth is another Moon or Star. 4^^

The E^nhf feveral Motions , according tofo-
- - - — - — - - pernicpj-

The Table,

\9
a-

<a •

f8
51

^3
he

?l
:cn

\99

in
the

hi'
he

80
8^
o-

4^!

pernicus. . ^ , . , 49f

Jhc 54r^i^ fitundum mm is Immntable, though

not Immoveable. 49 1

• the Natural Place. 4^2
thc£m)^x Centre keepctb h5J? in her Natural

Place

Thef^rf'^, in whatScnfe it ^^^ahfolt^flhti^ixA
to be in the lowcft part of the World. ^96

The firft sencral Conclufion of the impoffibi-
lity ofW/»^and Flowing the Immobility of
The Tcr reftrial Globe being granted. 3 8 o

the Periods of EU/ngs and Flo wings, Diurnal,
Monethly, and Annua)- )

Varieties that happen in the Diurnal Period of
thcf^i/^j^iandFlowihgy. V ^ . .-^

the Caufes of £^%i and Flowings alledged
byaModernPhylofapher. 382

'Rh: Caufe of the E^^/«.^ and Flowmg a^irribcd

^tothcMoonbyaccrtai^FtfHate. ^ 385

tieCaufeof theW.., dr. referred by^Hye-
ronimus Borrius and other Penpatcticks , to
the temperate heat of thcMqon. 3»5

Anfwersto the Vanities alledged as Caufes of
the £^^/«^ and Flowing. n.^nM nPi!,

proved impolTible that there (hould natu-
rally be any and Flowing , the Earth
being immoveable, ^ r c u vl

"ftemoft potent and primary Caufc of the
% and Flowing. . 390

Sundry accidents that happen m the mmgs

^ and Flowings.

^eafons renewed of the particular Accidents

obferved in the Bb^ings and Flowings. 3i?3
Seqond Caufes why in fcveral Seas and Lakes

there are no Bhl^ingj and Flowings. 394
theReafonV^hythe EM«i.^. and Flowings fo
^ the moft part, are every Six Hours. 35^ 5
the Caufe why fome Seas though very long,

fuffer no Shining and Flowing. 395
%«..aid Flowings, why greateft m the Ex-

trcm!tieso£ Gulpbs, and leaftm the middle

parts A -J

A DifcaVion of fome more Abftruce Accidents
obferved in the B^ing and Flowing. 396

the Mng and Flowingmay dependon the Di-
urnal Motion of Heaven- 4 4

the £^^/.,^ and Flowing cannot dependon the
Motion of Heaven. , .. . i^Ji

^ Oiuks of the Periods of the El;hn^s and
blowings Monethly and Annual, at large

^flisned . .

the l^onethly and Annual alterations of the

mings and Flowings , can d^P^"^^^.^'

thing , fave on the alteration of the Additions
and Subrradions of the Diurnal Period from
the Annual. 4^^
Three wayes of altering the proportion of the
Additions of the Diurnal Revolutions' to
the Annual Motion of the 6"to^andFiow-
ing.

£^^/>/ and Flowings are petty things , m
comparifon of the vaftneffeof the Seas, and
the Vclocitv oi the Motion of theTareflrial
Globe. ' 4^7

Effect and EfeSs.

Of anew Effe^ its neceifary ibat tb^Viufe lie

likewife new. . ^
T^e Knowledge of the Efe^s contribute to the

inveftigation of the Caufes. , 3 So

True and Natural E/^^f follow without ditti-

culty. ... 387

Alterations in the E/.(^/ argue alteration mttie

Caufe. . 407

E L E M £ N T s, their Mottons.Widc
Mot ion.

Encyclopedia.

Subtilties fufficiently infipid, ironically fpokcp,
and taken from a certain Encycb^edU, 1 5 5

Experiment $•

Senfible Experiments aretobe preferred before
Humane Argumentations. ?';335 4»-

It is poodtobe very cautious madmittmg tx-
pMts for true, to thofe that never tryed

"Experiments and Arguments agamft the Earths
Motion , feem fo far concluding , as they lye
under Equivokes

The Authority of Senfible Bxpmnants and ne-
ceffaiy Demonarations in deciding ot Phy-
fieal Controverfies. 43 f

Eye.

The Circle of the Pupil of the E^^tf contra(£leth
and enlargeth. r o r?*^

How to finde the diftance of the Rays Con-
courfe from the Pupil of the hjc.

Faith.

mh more infallible than either Sco^c g

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

The Table:

Rcafon.

475

Fire.

Fire movcih diredly upwards by Nature , and
round about by Participation , according
to Ariftotle.

It is iraprobabie that the Element of Firg (hould
be carried round by the Concave of the
Moon. 4^5

Figure and Figures,

F/V«ytfisnotthe Caufe of Incorruptibility , but
of Longer Duration. 65

The perfedtionof Figure appeareth in Corrup-
tible Bodies, but not in the Eternal. 6p

If the Spherical F/gure conferred Eternity, all
■ things would be Eternal. 6p

It is more difficult to finde F/^»r// that touch in
a part of their Surface , then in one fole
" point. • 185

The Circular Figure placed amongft the Poilif'
' of Mathematicians. ■ 186

Irregular Figures and Formes difficult to be in-
troduced. 187

Superficial figures increafe in proportion dou-
ble to their Lines. 304

Flexures.

The neceffity and ufc pi Flexures in Animals^
for varying of their Motions . 232

F OS GAR I N I.

..Iji- , y ■ : •

Fofcartm his JRecoticiltng of Scripture Texts
with the Copernican Bjpothefis, 473

G E*N E R A B I L I T V.

generAhilii) and Corruptibih'ty arc onely a-
mongft Contraries, according to Arift. 16

Generabilitj and Alterability are greater perfedi-
ons ill Mundane Bodies, then the Contrary
Qualities. 44

G E o M E T R I c A L, and Geometry,

Geometrical lytxsxonikxmQns of the Triple Di-
mcnfion, 4

Qeometricd Exaaneffe ncedlefle in Phyfical
^ Proofs. 6
j^riftotle taxcth Plato for being too ftudious of

Geomt"

Geometry. ^ 334

Peripatetick Phylofophers condemne the Stu-
dy of Geometry , and why* . 4^^

G I t B B »i T.

The Magnetick Phylofophy oiWi^- ^11^^* ^^4
The Method of Giihrt 'm his Philofophy. 3^7

Globe.

Our Gla^e would have been called Stone, inftea^J
of Earth , if that name had been given itiQ
the beginning.

O D.

God and Nature do employ themfelves in eating
for Men , as if they minded nothing elfc. 33^

An Example of Goiis care of Man^kind , tak^n
fromthe Sun. . ii^

God hath given all things an inviolable Lav^^o
obferve* 4**

Great.

Great and Small, Immenfe, &c. arc Relative
Terms. 334

Gravity.

Grave ] Vide Bocij,
Grawty and Levity , Rarity and Denfity t

contrary qualities. . 3^

Things Grave had being before the Com^o^^

Centre of Gravity,
Gravi^ and Levity of Bodies dcBncd. 4^3

Gun and Gunnery.

The Reafon why a Gun (hould feem to'^carry
farther towards the Weft than towards tftc
Eaft.

The Revolution of the Earth, fuppofed , tH
Ball in the Gun ereded perpendicularly^ dot"
not move by a perpendicular , but an incH'
ned Line.

It is ingenuoufly demonftrated , that,the Bart^
Motion fuppoied , the Shot of Great O^f^^
ought to vary no more than in its Reft. ,

The Experiment of a Running Chariot to nnd
out the difference of Ranges in Gunnery* 14^

A Computation in Gunnery , how much the
Ranges of Great Shot ought to vary fr?«»
the Mark , the Earths Motion being
Gralltcd.

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

The Table.

\^
le

Heaven.

^tdve/i an Habitation for the Immortal
Gods. 26
heavens Immutability evident to S enfc. 26
^^iien Immutable , bccaufe there never was
. any Mutation fccn in it. 34
One cannot (faith ArifiotU) (peak confident-
ly of llcav:n , by reafon of its great di-
ftance. 4»
The fubftance of the Heavens impenetrable, ac-
cording to ^r//?/??/^. 54
The Subflance of Heaven Intangible. 5 5

Many things maybe in Heaven, that are Invifi-
bletor.s. 334
|there are more Documents in the Open Book
of Heaven , than Vulgar Wits arc able to
Penetrate. 444
^'Aven and Earth ever mutually oppofed to each
other. 480
%ich arc really the Greater Lights in

and which the lelfcr. 4^4
^^n'en is not compofed of a fifth Effence, differ-
ing from the Matter of infcriourBodies.494
heaven is no Solid or Denfe Body , but
Rare. 4^4
Chrift at his Incarnatiou truly defcended from
Heaven, and at his Afceniion truly afcendcd
into Heaven. ^96
Oftlie Firft, Second and Third Heaven* 497
^ioven in the Senfe of Copernicus , is the fame
>with the moft tenuous ifether , but different
from Paradice , which excells all the Hea- .
^ens, ^99

fc. S T.

E L L-

^^U is in the Centre of the Earth , not of the
World. 4^0

fi L I X.

jjeiix about the Cylinder may be faid to be
a Simple Line, 7

Hypothesis*

the true Hypotkfo may difpatch its Revoluti-.
ons in alhorter time inlefler Circles, than
in greater , the which is proved by two
^^pks. 41^

5s $T.

A Jeji put upon one that offered to fell a cer-
tain Secret of holding Corre^ofidcncc at a
Thoufand Miles di.^ance,

A JeHoi a certain Statuary. 5^4

Impossibility and Impojpbilities.

Nature attempts not Trnf aJJibilittts, i o

To feck what would f ollow upon an ImfoJJihi'
% is Folly. 22

Incorruptib ility.

JncorruptihfUtj cflcemed by the Vulgar 9 out of
their fear of Death. 47

Infinity.

Of Infinity the Parts arc not one greater than
another , although they are comparatively
unequal. io5

Instrument and Injirnments.

Inflrnments Aflronomical very fubjeft to Ef-
rour. 262

Copernicus undcrftood not fome things fof
want of Mrumenis, 33 B

A proof of the fjnall credit that is to be given
to Aftronomical InHmmenis in Minute Ob-
fervations. , 3JI

Pirolomy did not confide in an Infirument made
by Archimedes. 352

Jyftrument* of Tycho made with great Ex-
pence. 352

What Inftrumenis are mofl: apt forexa(a Obfer-
vaiions. 352

Inventors.

The Firfl Inventors and Obfervcrs of things
ought to be admired. 3 70

J o s H u A H.

The Miracle of Jofhuah in commanding the Sun
to ftand ftill > contradids the Ptoloniaick
. Syftem. 45<*

Jofhuahs Miracle admirably agrecth with the
Pytjiagorick Syflcme. 457

V v

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

^he table.

IrO K.

L I N E«

Its proved that Iron confiftsof parts morefubtiJ,
pare and compad than the Magnet. 370

The Rigk Lm and Circun:ifercnce of an in&-
nite Circle arc th w fame thini:. 34^

UP I T E R.

Jupiter and Saturn do cncotnpafTe the Earth,
and the Sun. 258

jC/d^i/^r augments kflc by Irradiation , than the
Dog-Star. 305

Kepler.

The Argument of Kepler in favour of Coper-
nicus. 24^

AnExplanation ofthetrueSenfe oiKe^Ur , and
his Defence. 243

The feianed Anfwer of Kepler couched in an
Artificial Irony. 244

Kepler is, with rc(pC(5l, blamed. 422

Keplers reconciling of Scripture Texts whith the
Copernican Hypothefis. 461

K N O W)

The having a pcrfcd Knmledgc of nothing,
inakcth (ome beleeve they underftand all
things. 84

Gods manner of Knowing different from that of
Man. 87

The great Felicity for which they are to be en-
vied 5 who perfwade themfelves that they
K«^'»' every thing. 164

Our Knowledge is a kind of Reminifcence, ac-
cording to Plato. . 16^

Light.

U^k rcfieded from the Earth into the
Moon. 5^

The Reflex Ught of uneven Bodies is moreuni-
verfal than that of the fmooth , and why. 62

Jhc more rough Superficies make greater Re-
flexion of Ught than the lefle rough. 6$

Perpendicular Rays of Ught illuminate more
than the Oblique, and why . 55

The more Oblique Rays of Ught illuminate
Icffc;, and why, 65

Light or Luminous Bodies appear the brighter
m an Obfcurc Ambient. 74

Lawyers.

Contentious lavpyers that are retained in an ill
Caufe, keep clofeto fome expreffion fallen
from the advcrfc party at unawares. 3^4

Look Ing-GlassES-

Fiat Looking-Gbffis caft forth their Refleaion to-
wards but one place 5 but the Spherical ev^"
ry way. P

L Y N C E A N.

IhcLpcean Acadcmick thcfirft Difcovcrcrof
the Solar fpots^ and all the other CeU^l^^^
Novelties.

The Hiftory of his proceedings for a I^'fJ
time 5 about the Obfervation of the So^^
Spots.

Magnet.

Many properties in the Magnet', . 3^^
The A/ armed takes up more Iron, t^^^

when unarmed. 3^^^
The true caufe of the Multiplication of Vcrtu^

in the Magnet^ by means of the Arming.
A fenfitle proof of the Impurity of the ^i^i'

net. 37^
The feveral Natural Motions of the Mg'

net, ^
Philoiophers are forced to confcffe that the

Magnet is compounded of Celcflial Subftan'

CCS, and of Elementary. 3/^
The Error of thofc who call the Magnet a mi^

Body, and the Terreftrial Globe , a fii^^P^

Body. ^V
An improvable Effedadrnked by Gilbertusi^

x!i[iZ Magnet. 3 7^

M A G N E T I c K Fhilofophy-
The 2dagnuick Hibfiph^ of William ^'^^j^^^'

Magnitude.
The Magnitude of the Orbs and the Velocity
of the Motions of Planets anfwer proporti-

onably,

The Table.

onab[y ; as if dcfccndedfrom the fame
place. , .

Immenfe Mr.onitudes and Numbers are incom-
prchenfiblc by our Undaftaadin^^s. 332

Mars*

^an ncceflarily includeth within its Orb the
Earth, and alfo the Sun

Marszi its Oppofuion to the Sun , feems fixty
times bigger than towards the Conjunai^-
on. , ^

A^^r/ makes an hot aflault upon the.Coperni-

canSyfteme.

M A R s I L I u s.

^ignor C4ar Mdrfiiiffs obfcrvcth the Meridian
to be moveable.

M e d I c E A N.

The time of the Mcdicean Planets converfi-

^h^Medicean Planets are as it were four Moon s
zhoni ^upttr. ^ '

Medi terra n-

hkerranean Sea made by the Scperation of
Abila and Galpcn. 3 5

'he Vovaecs in the Maiterran from Eaft to
Weft are made in (horter .times than from
Weft to Eaft. 4^3

Mercury.

The Revolution of Mercurf concluded to be
about the Sun , within the Orb of Venus.2^8

Itercurj admiueth not of clear Obfervati-
ons.

Moon.

The Moon hath no Generation of things ,
like as we have , nor is it inhabited by

Men. . . u-

In the Moon ^ay be a Generation of things dif-
ferent from ours. , 47
There may be Subftances in the Moon , veiy

different from ours. , r ,

The firft rcfcmblance between the \Uoon and
Earth, which is that ot Figure , is proved,
by their manner ot being illuminated by tlic
Sun

The^fecond rcfemblance is the Moons being

p a-

Opacous, asthcEmhi ^ a8

The third rcfcmbla.icc is the Moomh^ino Denlc
and Mountainous as the Earth. 49
The fourth rcfcmblance is the Moon^ being di-
ftin^uiQied into two different parts for Cla-
iity*and Obfcuiity , as the Tcrieftrial Globe
into Sea and Land. 4^
The fifth rcfcmblance is Mutation of Figures 111
the Earth, like thofe of the iT^oi?^ , and made
with the fame Periods. 4 ^

All the Earth fccth halfe oncly of the Moon,
and halfc onely of the Moon feeth all the
Earth ^ . . 5i

Two Spots in the Moon , by which it is percei-
ved that She hath refpe(S to the Centre of
the Earth in her Motion. 5 ^

Li^ht refledlcd from the Earth into the Moon.s^^
The fixth rcfcmblance is that the Earth and
Moon interchangeably illuminate. 5 1

The feventh rcfemblance is that the Earth and
Mjon interchang;cably Ecclipfe. 55
The Secondary Clarity of the Moon cft:emed
to be its Native Light- 54
the Surface of the Moon more fleek then any
Looking- Glafle. ^ 5 J

The eminrncicsandCaviticstrrthc;i/^i7«,arcillu-
fions of its Opacousand Pcrfpicuoui> pa-'ts. 5 5
The Moom Surface is (harp , as is largely pro-
ved. 57
The y[oon , if it it were (leek like a Sphc. icil
Looking- Glaffe , would be invifibie* 60
^ & 6z

The apparent UnevcnncfTcs of the Moo^f Sur-
face aptly reprefented by Mother of

Pearl. . ^ r u

The apparent VnevennefTes of the Mom cannot

bcimitatcd by way of more and IcfTe Opa-
city, and Pcrfpicuity 71

The various Afpccts of the cS'Hoo^i imitable b /
any Opacous matter. 71

Sundry Phsenomcna from whence the MoorJ
Montuofity is argued. 7 1

The Moon appears brightct by night , than by

The Moon beheld in the day time, is hke to ^
little Cloud. 7a
Clouds are no leflc apt than the iV/^70ii to be il^
luminatcdby theSun. 73
A Wall illuminated by the Sun, compared td
xhQMoon^ (bines no IcfTe than it- 7^
The third reflexion of a Wall illuminates more
than the firft of the Mccn. ^ 74

The Light of the Moon weaker than that o* the
Twy-light.

The fccondary Light of the i^oi^-^caufed t.y tn-
Sun, according to fome, '^^

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

the fecondary jLigbt of the Mcon appears

inform of a Ring, bright in the extreme

Circumference, and not in the midft, and

why. 77
The fccondary Light of the Moon, how it is to

be obfcrved. 7^
rhcMccn^Diicus in a Solar Eclipfe can be feen

onely by Privation. 7^
Solidity of the Moons filohc argued from its

being Mountainous. Si
The fccondary Light of the Moon clearer before

the Conjundiun than after. 82
Thcobfcurcr pai rs of Moon are Plains, and

the more bright Mountains. 83
Long Ledges ot Mounpins about the Spots of

the Moon, ■'- - ' ^ ^3

There are j^-^t generated in the Moon things

like to ours, but if there be anyProdudi-

ons, they are very different. 83
The M^on not compofed of Water and

Earth. * 83

Thofc Afpcds of the Sun ncccflary for our

Prodiidioiis, are notfo in the Moon. 83
Natural Daycs in the lAoon are of a Moncth

Jong. 84
To i\v^MoQn theSundcclincth with a difference

of ten Degrees , and to the Earth of Forty

fcven Degrees. 84
There are no Rains in the Moon, 84
Ih^^Moon cannot fcperate from the Earth. 295
The Moons Orbe erivironeth the Earth , but not

the Sun. 299
TheM«7f« much difturbcth the Order of the

other Planets. r t. • ^

The Uoons Motion principally fought in the

Account of Eclipfcs. ^16
The Uooa is an ALthcreal Earth. 492

Motion and Motions.

Motion o^V^o]^6t^. VidiZ Projeas,

The Condiuonsand Attributes which differ the
Cekftial and Elementary Bodies depend on
the Uotions affigned them by Ariftotle. 2 5

Pcripatcticks improperly alTign thofc Motion sio
the Elements for Natural with which they
never were moved, and thofc for Preternatu-
ral with which they alwayes move. 3 3

Motion^ as to the things that move thereby, is as
if it never were , and fo farre operates, as it
relates to things dcpr ved of M^?//V«. 9^

Uotion cannot be made without its moveable
Subjca. 104

Motion and Reft principal Accidents in Na-
ture, rf ^ c

Two things neccflary for the perpetuating of a

h\0'

Motion ■ an unlimited Space; and an incor-
ruptible Moveable. J^^^

Difparity in the Motions of a Stone falling from
the Round Top of a Ship , and from tne
Top of a Tower.

The Motion of grave Pendula might be perpe-
tuated , impcdimcHts being removed. 2 05

Whence the Motion of a Cadent Body iscol-
leaed.

The Motion the Ey c argueth the Mf //^'/» 0"he
Body looked on. 224

Different Motions depending on the Flu<5tuati-
on of the Ship.

Our Motion may be cither interne, orcxterne,
and yet we never perceive or feci ir.

The Motion of a Boat infenfiblc x6 thofe that are
within it^ as to the Senfe of Feeling.

Thc'Mo//^»of a Boat fenfible to Sight joyned
with Reafon. 22P

Afimple Body, as the Earthy cannot move with
three feveral Motions, 23 1

Motion and Reft arc more different than Right
Motion and Circular. J

One may more rationally afcribe to thcEartn
two intern Principles to the Right and Cir-
cular Motion y than two to Motion and
Reft. , ^37

The diver/Ity of Motions helpcth us to know
the Diverfity of Natures •

Bodies of the fame kind , have M<^//^^' ^nit
agree in kinde. ^3?. •

The greatneffeand fmallncne of the Body make
a difference in Motion and not in Reft. 24^

Every pen file and libratcd Body carried rou'nd
in the Circumference of a Circle acquireth
of it fclf a Motion in it fclf cqujl to the
fame. 3^^

Two forts of Motion in the contaiiling v eflel
may make the containing Water to riic and
fall. ^5^7

An Accident in the Earths Motion impoiiibkto
be imitated. -j^^*

Absolute Motion : Things faid to
move according to certain of their parts?
and not according to their whole, may not
be faid to move with an Abfolute Motion, but
fer accidens, 4^.^

Animal Motion: The Diverfity of
Mof/tf/ij of Animals, depend on their f^^^^
ures.

The Flexures in Animals are not made for vary-
ing of their Mf^/^>«J. ^5-*
The Motions of Animals are of one fort. ^ 3 *
TheMof/V«y of Animals are all Circular.
Secondary Mf^/f/^ of Animals dependent onttic

The Table.

^^nlmals would not grow weary of their Mo-
tien , procccdin^ji; as that which is alTigned
to the Tcrreftrial Globe. 244

"Hie Caufc ot the wearincfTc that attends the
i^oti0A of Animals. M4

The Motion of an An/mal js rather to be called
Violent than Natural. , ^/^^^

Annual Motion: The hnvimlMouon
of the Earth muft caufe a'conftant and ftron^
Winde. ^ .

ThcErrour of the Antagonift of Copernicus 1^
manifeft,inthathedcclarcth thatthe Annual
and Diurnal Motion belonging to the Earth,
are both oneway , and not contrary. 23$

The Annual lAotionoi the Earth mixing with

, the Motions of the other Planets, produce

^ extravagant Appearances. ^96

left, Annual Motion, and the Diurnal , ought
tobcdiftributed betwixt the Sun, Earth, and
firmament. , .

^taming to the Earth the Annual , it mUlt ot
necemtvhavc the Diurnal Motion alTigned to

^hefole Annual Motion of the Earth , caufeth
great inequality in the Motions of the Pla-
nets

A Dcmonftration of the inequalities of the three
fupcriour Planets dependent on the Annual
^^,r/<7« of the Earth. 3i«>

iHe Annual Uotion of the Earth moft apt to
tender a reafon of the Exorbitance of the
five Planets. , ^ ,

Argument of Tychoagainft the Annual Moti-
on , from the invariable Elevation of the
Pole. , 33?

^pon the Annual Mw/^of the Earth, alterati-
on mav cnfuc in fomc Fixed Stars, not in the
Pole

The Parallocifmeof thofc who believe that in
4e Ann?al ^oticn great alterations ;^e to
be made about the Elevation of the Fixed
^ Stars, is confuted. 34i
Enquiry is made what tnutations , and m what
^tars , aretobedifcovered by means of the
, Barths Annual Motion. ^ 34^
Aftronomers having omitted to mftance what
alterations thofe are that may be derived
from the Annual Uotien of the Earth , do
thereby teftifie that they never rightly un-
derftood the fame. r'^
'Hie Annual Motion made by the Centre ot tne
Earth under thcEcliptick, and the Diurnal
nation made by thd Earth about its own
Centre

^^caions aaainft the Earths Annual Motion
taken from the Fixed Stari placed in ^the E-

cliptick. .
An Indicc or Obfcrvation in the Fixed Stars like
to that which is fccn in the Planets, is an A r-
gument of the Eaiths Annual Motion, 347
The Suns Annual Motion how i: coracth to
pafifc, according to Copernicus. 3^5
The Annual and Diurnal Motion arc confident
in the Earth. 3^-
Three waycsot altering the proportion of drj
Additions of the Diurnal Revolution to the
Annual Motion, . 4^9

The Earths Annual Mtff/^« thorow thcEcliptick.

unequal, by reafon of the Moons Motio^i. 415
TheCaufcsofthe inequality of the Additions
and Subftradions of the Diurnal Converli-
' on from the Annual Motion, 418
Circular Motion: Circularand Right
Mt'/zV^arefimple, as proceeding in fimplc
Lines. . , v : f

The Circular M(j^/V« is never acquired Natural-
ly , unlefle Right Motion precede it. 1 8
Circular Motion perpetually uniforme. .18
In the Circular Motion every point in the Cir-
cumference is the beginning and end. 20
Ci^\x\z'c Motion ovidy isXlniiomt. , . 20
Circular Motiin may be continued perpetu-
ally. . , 20
Circular Motion onely and Reft are aft to cpn^

fcrve Order, . .

To the Circular Motion no other laotim is con-
trary. '^^
Circular Motions arc not contrajy> according
toAriftotlc. ., ^ ^ ^ ^^"^

The Motion of the Parts of the Earth returning
to their Whole, may be Circular. 237
The Velocity in the Circular Mor/f « encrealeth
according; to the cncreafe of ihe Diameter
of the Circle. 242
Circular Motion is truly firaple and perpetu-
al. 495.
Circular Motion belongeth to the Whole Bo-
dy, and the Right to its Parts. , 49^
Circular and Right Motion are coincident , and
may confift together in the fame Body. 49<5
Com mon Motion: A notable Inftance
of Sagredus , to (hew the non-operating of
Cotiimon Motion, 15^
An Experiment that fbewcth how the Com-
mo^Motion is imperceptible. 224
The concurrence of the Elements in a Com-
mon M^//o/4 imports no more than their con-
currence in a CommonReft. ^39
CommonMo//o«isasif it ncvcrwere. 225'^."^^
Compressive Motion: ComP5^"*y^
Motion is proper 10 Gravity, Exteniive .0
Levity. '^^^

Cori-

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

The Table.

Contrary MoT

racnt which plainly Ihcvvs that two Con
irn! V UodoM may agree in the fame Move-
able. - ^ 3^3
The parts of a Circle regularly moved about its
ownCcntlc , move in diverfe times with
Contrary Mcticns, ' . 3^^
DESCHN^1^^G Motion t The Inclination of
Grave Bodies to the Motion of Dcicent , is c-
qual to their refiftance to the Motion. ot
Alcent.

The Spaces paft in the Defcending Motion ot
the falling; Grave Body , are as the Squares.of

their times. u J5f

The ;j/o/M/ofDercenthe|o"gs nottotheTer-

reftrial Globe , but to its parts. 3^^
DivRNAL Motion : The Wal ^.//^
feemethComraunc to all the Vniverfe , the
Earth oncly excepted- 97
Diurnal Mona rchy it (bould more probably
belong to the Earth than to the Reft of the
Vnivcdc. , ^.

The ft-ll Difcoutfeto prove that the Diurnal
Mction belongs to the Earth. 99
The Diurnal Motion caufeth no Mutation among
Cekftial Bod.es , but all changes have relati-
on to the Earth. , ^. ,
A ftcond Confirmation thatjthe Diurnal Moti^
on belongs to the Earth. loo
Athird Confirmation that the Diurnal Motm
belongs to the Earth. i o i
Afonrth, fifth, and fixth ConfifmatLon that the
Diurnal belongs to the Eatth. toi
Aleventh Confirmation that the Diurnal Mo^
belongs to the Earth. ^^3
If the Diurnal Motion (hould alter, the Annual

period would ceafe,
Local Motion ; Local Motion of three
kinds, Right, Circular, and Mixt. 6
An entire and new Science of our Academick
fGalileol concernino; Local MotPon. 198
Mixt Motion : Of Mixt Motion we fee not
the part that is Circular , becaufe we pertake
thereof. .
Ariftotle granteth a Mixt Moim to Mixt

Bodie;.. . ^ ^ r

The Motion of Mixt Bodies ought to be fuch as
may refult from theCompofitionofthe Mo-
tions of die fimple Bodies compounding. 57 5
Natvral Motion : Accclleration of the
natural Mouon of Graves is made according
to the Odd Numbers bcgmnma at Uni-
ty. '^.^
>;atural Motion chan-^cth into that which is
Preter-Natural and Violent. 212
Pk^oressivu Motion : The ProgreflflVC

Mo-

An Experl- Motion may make the Water in a Veflel t6
run to and fro. 3

Right Motion: Sometimes Simple, ana

fometimes Mixt , according to Ariftotle.
Right Motion impoflible in the World exactly
Ordinate. \o
Rigjht Motion Naturally Infinite. ^
Right Motion Naturally Impofiibie. ' .
Right Mction might poflfibly have been m tne
Firft Chaos. ? ^

Ri^iht Moticn is ufeful to reduce into Oracr

thm^s out of Order. *
'Kx^t Motion cannot naturally be Pcrpcwal. 2
Right Motion afiigned to Natural Bodies , to re-
duce them to perfcd Order, when removeo
from their Places. "
Rieht Moticn of Grave Bodies manifeft
Scnfc.

Right Motion with more rcafon afcribed to tne
Parts, than to the whole Elements. 3 3
Right Motion cannot be Eternal , and conic-
qucntly cannot be Natural to the Earth, ip
Right Motion feemethto be wholly excludedio
Nature. ^V,
With two Right Motions one cannot compos
Circular dM^otions, Jc
Right Motion belongeth to imperfect 15oaiu,^
and that are out of tbeir Natural Places. 4^>
Right Motion is not Simple.
Right Motion is evet mixt with the Circular, 4>'>
Simple MoTior^ peculiar ondy to Simply

^odkS. n 1 r the

Thrkbstrial Motion Col!c(3ed frO^t^^

Stars. .
The Parts of the Tcrreftrial Globe accelerate
and retard in their Motion, ' ^ • 3 °

One fmglc Tcrreftrial Motion fufficcth not to
producethe Ebbingand Flowing. 4^.^
Uneven Motion may make tUC w ^_

a Veflel to Run to and fro; ^ j

The Mixture of the two Uoticns Annual an^
Diurnal , caufeth the. unevcnncite in -
Motion oi the parts ot the ^^^'^^^^'^^^

Globe.

Its qucftionable whether defcendingBo
Move in a Right Line. , ^ ^ ^od'^vs

Ariftotles Argument to prove that Grave i|
Move with an inclination to arrive ^
Centre. r ^^is

Grave Bodies ^foz;^ towards the Ccnti'C

Centre of the Eai ihper Acci<}ens, j.^

Things forfaking the place which was "^^j^^^i^;
thembyCreation^arcfaidtoil^^'^'^ ^'d

The TMl

?4
be
^9
itc

lies

lies
the

the

(tiy>

and naturally tend to rcuirn back to the
fame. 4>?2

Moveable, &*c,

Yh:.

hMov:dkhQ\n^ in the ftatcof Reft Qiall not;
move unk'lTc it have an inclination to fome
particular Place. 11
The MovedU accellcrntcs its Motion in going
towards the Place whither it hath an inclina-
tion, n
V^zMoveaUe departing from Reft goeth thorov7
all the Degrees of Tardity. 11
The Moveable doth not accelerate favc only as
it approacheth near toitstermeofRcft. 12
To introduce in a ^(71^^^^^ a certain Degree of
Velocity, Nature made it to movcin a Ri^ he
Line. 1 2

The cMoveaWe departing from Reft palTcth
through all the Degrees of Velocity without
ftayinginany. - 13
T^e Grave Moveable dcfcending , acquircth
Impetus fufficient to re-carry it to the like
height. . }l

The Impetus of Moveables equally approaching
to the Centre arc equal- 14
Vpon an Horizontal Plane the Moveable lycth
ftill. J. V 14

A ilngle Moveable hath but one only Natural
. Motion J and all the reft are by particip^
tion. . 103

A Line dcfcribeil by a Movedle in its Natural
t)efcent, the Motion of the Earth about its
own Centre being prefuppofed^ would pro-
bably be theCircuaifercnce of a Circle. 14$
A Moveable falling from the top of a Tower
tnovcthin the Circumference of a Circle. 146
A Moveable falling from a Tower moveth
neither more nor Icflej then if it hadftaid
alw ayes there. 146
A Movenble falling from a Tower movcth with
an Uniforme not an Accelerate Motion. 146
^he Cadent lAoveable ^if ii fall with a Degree of
Velocity acquired in a like time with an
Uniform Motion, it (hall pafte a fpace double
to that paired with the Accelerate Mo-
tion. 202
Admirable Problcn^s of Moveables dcfcending
, by the Quadrant of a Circle, and thofe
dcfcending by all the Chords of the whole
Circle. 412

M u N J) A N t.

^i^ndane Bodies were moved in the beginning
. in a Right Line , and afterwards circularly,
'ccordin^to/^/^^tf. n

N A-

A T U R A L.

That w^iich is Violent ca:nnot be Etcrnail, and
that which is Eternal cannot be Natural, 1 1 6

Nature, and Natures. •

Nitureintmp^s liDt things impbfiTible to be
effected. 10

Nature xicvcr dotli that by. many things which
may he done by a few. ^9

Nature firft made things as fhe plcafcd , and
afterwards capacitated Mans underftanding
for conceiving of rhcm. ~ ^ ^'338

From Common Accidents one cannot, know
different Natures. - ,138

Nature's Order is to make thfelcffer Orbes to Cir^
dilate in (horter times.^- and the bigger in
longer. .''-^ .2^^

That whieh to us is hard to beunderftood^ts with
'Nature cafic to be cifcded. ^ ^03

iV^rrwr^lcccping within the bounds afligned her,
littlccareth that her Methods of opp'^rating
fall within the rcaih of Humane Capacify.43|

Natures Adions no I'efs admirably difcbver God
to us than Scripture Diaions. 434

T R V E S '

The Original of theV^fn^^y according to Ariftd-
tle, and according , to Phyfitians. 91

The ridiculous Anfwcr of a Phylofopher deter-
mining the Original of the Nenes> 9 1

Object s.

Obje^s, the more Vigorous they are in Light^tltfe
more they do fecni to cncreafc. 505

That Remote obJeJifj appear (o fmall is the
Defedt of the Eyc^ as is dcmcnfl rated. 337

In Objeefshi Remote and Luminous, a fmall
acccffion or reccflion is imperceptible. 356

r I N I O N Sr

It's all one, whether Opinions are new to Men, or
Men ne w to Opinions, 7 7

O R B and Orbes*

The greater Orbes make their Converfions in

greater

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

greatcrtimes. , ^ , 9' 35i

It's more rational, that the Orh Containing and
the Parts contained do move all about one
Centre, than about divers. ^95

Passions.

infinite r^j[pons are perhaps but one onely. 87

Pendulum, and Fettdula.

FenAulamight have a perpetual Motion, impedi-
ments being removed.
The/>e«^«/*«'banging atalonger thread makcth
its Vibrations more feldome than the P^^^/^-
ium hanging at a Oiorter.

TheVibra?ionsof the fame P/«^«/iii« are made
with die lame frequency, whether they be
fmall or great. , , , „ ^, ^''^

The caufe which impcdeth the Tendulumt and
rcduccthittorcft. ^ ^ ^.^"^^

Tke thread or Chain to which the Pendulum is
fattened makeih an Arch,and doth not ftretch
it felt ftraight out in its V ibrations. 207

Two particular notable Accidents in the Pe»dda

' andtbeirVibraiions. 4^^

P t A N ET S.

The approxiknation and receffion of the three
fuperiour Fhmets importeth double the iuns
diftance. ^^f

The difference of the T'Unets apparent ^^f^Y!
tudelefTc in Saturn than in Jupiter, and IcUC
in Jupiter than in Mars, and why. ^'^99

the Station, Direaion, and Retrogradation ot
the is known in relation to the fixed
Stars. 347

The particular Struftures of the Orbes ot ttic
Planets not yet well refolvcd. 4{^^

The PUnets places may more certainly he
affigred by this Dodrinc, than by that ot
Ptolomics great Almageft. 4^^

Plato.

PUtohc\^^ that Humane underftanding pertook
of Divinity, becaufe it underftood NuJO^

bcrs. h
fUto his ^Enigma , and the Interpretation 01

it, 4^
Pole.

The invariable Elevation of the ?o/(?urgedasan

Argumentagainft the Annual Motion. 33
AnExample to prove that the Altitude of
ought not to vary by means of the Eartn^
Annual Motion. 34

P.ric4^^^HPhylofophy unchangeable. 4»
A &refolution of a ccn^n PerrpatetUk
^ Phdofopher to prove the Right Line to be Ae

ftiorteft of all Lines.
The Paralogifme of the faid Pertpatdick who
proveth Ignotumpcr ignotius. 183
The Difcourfes of Piripatetickf full of Errors and
Contradidions. 37^
The Peripamch perfecuted Galileo out of envy

to his happy Difcoveries P^yl^^^P^y- .4^7 ^ ^ - p^j„,^ f„ Sciences , any Parado^
TheP^r/A^indefeaof Reafo^^^ ''^t.^ay be maintained.
Scripture foi Arguments agamft their _ > „ . . , _.....«n.. ..C^Ae irt

Power.

Of an infinite P^wer one would think a greater
part fhould rather be imployed than a
lefTcr.

Principles.

Adverfaries.

their
429

may be maintained. *
Contrary Principles cannot naturally rehde i"
die fame Subjea.

Phylosofhers.

Itisnoiiu(l,thatthofe who never Phylorophatc,
Ihould ufurp the title of Phjlofophers. 96

PhyloSophy.

TKcDifp"^"-"^ Contradiaions oiPf>j>lofophers
may conduce to the benefit of Phhfiphy. 2 5

A cunning way to gather thylofophj out of any
Bookwhatfoever. 9»

Pro}e c^, &c.

The Pro\e&, according to Ariaotle, is

ved by virtue imprelTed > but by the ^ac-
dium. .

Operation of the Medium in continuing inc
Motion of theTr^VtJ?. .^^ll

Many Experiments and Reafons againlt tne
Motions of ProjeBs afligncd by A^iftorie. 13 »

The Mediumdoth impede and not contcnLtnc

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

The Tahk-

the

the
the

Motion of Viojt^s. 134
An admirable accident in the Motion of Pro-

Sundry curious Problems touching the Motion
of Projects, T37

^^oje^s continue their ^^.Jt/V/J by a Fight Line

. jhat follows the dircdion of the Motion
made together with the ProjUient , whilft
they were CQnjoyncd therewith. ^ 154

The Motion imprciled by the Projicient is onely
in a Right Line, 170

The Projt^ moveth by the Tangent of the Cir-
cle of the Motion prcceeding in the inftant
of Seperation. 172

A Grave Proje^ affoon as it is feperated from

. the Vrojkknt , bcginneth to decline. 173

the Caufe of the Vroje5fhn encreafeth not ac-
cording to the Proportion of Velocity cn-
creafed by making the Wheel bigger. 189
^ The Virtue which carricth Grave Vroje£fs up-

]^Wards 5 is no leflc Natural to them than
the Gravity which moveth them down-

. wards.

P T o L o M Y5 &*c.

Inconveniences that are in the Syftemof P/^?-

lomy, .
holomies Syaem full of defers. 47<^
The Learned both of elder and later times dif-
fatislied with the \^(olpm(tick Syftcm. 477

Pythagoras, &*c.

'^}thagorick Miftery of Numbers fabulous. 3
^^thagorai offered an Hecatombc for a Geo-
metricalDemonftration which he found. 58
'^phagoras and many other Ancients enumera-
ted, that held the Earths Mobility. 437 &^6S

R A Y S»

Shining Objeds kcm fringed and environed
with adventitious Rdjf. 304

Rl ST.

Vide Amotion,
^^[i the Lifinite degree of Tardily. 1 1

R B T R O G K A D A T I O N S.

^^yooradAt'ms more frequent in Saturn , leflc
' frc que^K in Jupiter, and yet idle in Mars,

and

and why^.

The Rttrogradationr of V^nus and Mercury
dempnftratfd by Apcllonius and Coper-

^11

nicus.

C> A T U K N'.

Saturn for its (lownefTc , and Mercury for its
late appearing, were amongft thofe that were
lafl* obferved. 415

Scarcity.

Scarcity and Plenty enhanfe and debafe the ;^ icc

of all things.

o c H B I N E R.

Chriftophcr J'c>&^/;»tfrthe Jcfuithis Book of Con-
clufions confuted. 78 6" 195, & feq.'& 3 23

A Canon Bullet would fpend more than fix
daycs in falling from the Conca\^c of the
Moon to the Center of the Earth, according
to Sshe/ner. 195

Chriftopher Sckiner his Book entituled a^^elks
pojl Tahlm ccnfu red , and difproved . 3 1 3

The Obje<^ions of Scheiner by way of Interro-
gation. ; 1^6

Anfwcrs to the Interrogations of Schtiner. 336

Qucftions put to Sckiner , by which the weak-
nefle of his is made appear, 33^

S c 1 E N c t. s.

in Natural Sciences the Art of Oratory is of no
ufc. 40

In Natural Sciences it is not necefTary to feek
Mathematical evidence. 20^

S C R I P T U Fv E 3

The Caution we arc to ufein dctermi iing the
Scnfe of Script itre in difficult points of Phy-
lofophy. 427
Scripture fludioufly condefcendeJh to the ap-
prchenfion of the Vulgar. ^32
In dicuffing of Natural Qucftions , we oiigbc
not to begin at Scripture , but at Scnfible
Experiments and NecefTary Dcraronftra*
tions. W.
The intent of Scripture is by its Authority to
recommend thofc Truth:* to our beliefe,
which being un-intelligible, could no other
waycs be rendered credible 43 4

Y V y

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

rhe Tabled

<,cmme Authority to be preferred, even in Na-
tural Controverfiejs to fuch Sciences as arc
not confined to a Dcmonftrative Me-
thod. ^ , . 434

The Pen-men of Scripture y though read in A-
ftionomy , intentionally torbcar to teach us
any thing ot the Mature of the Stars. 43 5

The Spirit h:id no intent at the Writing ot the
Scripture , to teach us whether the Earth rao-
veth or ftandtth ftill , as nothing concerning
our Salvation, 43^

Inconvcnicncics that arifc from hcentlous u-
Scripturt^ to ftuffe out Books that
treat ot" Nat. Arguments. 43^

The Literal Senfc of Scripture joyned with the
univcrfalconfentof the Fathers, is to be re-
ceived without farther difpute. 444

A Text of Scripture ought no leHc diligently
to be reconciled with a Demonftrated Pro-
pofition in Phllofophy , than with another
Text of Scripture founding to a contrary

Demonftrated Truth ought to aflift the Com-
mentator in finding the true Senleof Scup-
ture. , r r

It was ncceflary by way of condelcenlion to

' Vulgar Capacities, that the Scripture Shom
fpeakof the ReftandMotion of theSun and
Earth in the lame ttianner that it doth. 447

Not onely the Incapacity of the Vulgar, but
the Current Opinion of thofc tirae^, made
rhc Sacred Writers of the Scripture to ac-
commodate thcnifelvcs to Popular Efteem
more than Truth. 447

The Scfipture liad much more rcafon toattirm
the Sin Moveable , and the Earth Immove-
able, than othcrwife. W

Circumfpcdion of the Fathers about impoling
pofrtive Scnfcs on Doubtful Texts of Scrip-
ture, ^ .451

Tis Cowardice makes the Ami- Coper mean fly
to Scripture Authorities, thinkingthercby to
affri£[ht their Advcrfaries. «

Scriptun (peaks in Vulgarand Common Points
aftcrthemanner Men. j • *

The intent of is to beobferved in Pla-

ces that feem to aftirme the Earths Stabi-
lity. 4<^4

Scripture Authorities that feem to affirm the Mo-
tion of the Sun and Stability of the barth,
divided into fix Chffcs. 478

Six Maximcs to be obferved in Expoundmg
Dark Texts of Scripture. 4^.^

Scripture Texts fptaking of things inconveni-
ent to be underftood itv their Literal Senle,
arc to be interprete d one ot the four waycs

named.

named. . f}c

Why the Sacred <r«r/7>f«r^ accommodates it Kir
to the Senfe of the Vulgar. 4^7

S E A.

The Seas Surface would (hew at adiftancc more
obfcurethan the Land. 4^

Theto/Refledion of Light much weaker tWn
that of the Earth.

The Hies are tokens of the uhevcnneffe ot tnc
Bottoms of Seas, 3 ;^

SelilucuS.
Opinion of Seleucus the Mathematician ^^P^

furcd

S E N S B.

He whodenieth Senfe, defcrvestobe deprive^

of it *
toff fheweth that things Grave move ad Mi-

dium , and the Light to the Concave. 2
It is not probable that God who gave us out

SenUs, would have us lay them ^^^f »

look for other Proofs for fuch Natural Points

as top fets before our Eyes.
iei^e and Reafon lefTe certain than Faitlt 47 >

Silver.

Sil'oer burnifhed appears much more obfcUT^
than the unburnllhed, and why. ^4

S I M P L I c I u s-

Simplism his Declamation.

Socrates*

The Anfwer of the Oracle true in judging
crates the Wifeft of his time.

Sorites-

The Forked Sylogifme called sopj^*;.

Speaking.

We cannot abftia^ our manner of ^/'^^'^^f
from our Senfe of Seeing. 4

S P H E R £•

1 he Motion of 24 ^^urs afcribed to

:hcft
e

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

The T ahle.

['Sfkre. diforacrsthc Period of the Infcn-

r^Sficre although Material ; touchetli the
MaferialPlancbutinoncpomtoncly. 82

The Definition of the5^W. , . ' "

A Dcmonftration that the ^phn^ toucheth ^thc

onely m one point , anu nu ^
Concrete. not peculiar to the

ble thltits Ccmrebeftable, thananyof us

Sphere of .ifli^i'^

The Spt^re of AHhUy greater in Ccleftial Bo-
dies than in Elimemary. »'

Starry Sphere.
Wearineffcrnoretobefearedinthe.^...^^^^^^
^ than in tbcTetTeftnal G bb 45
''S%CistKbeyct morcre-

V thofe mens difcourle , who argue

'St;';ttobetoovaftiatheCopc^^

tSjeC'S^-beheldf^^^^
ftance, misht appear as fraall as one lingic
Star. "

SprtERlCAt.

•'1)cmadewithonefole Inftrutnent. /

Spirit.
•TL \^ A r^r^ mtcnt to tcQcb US whethcf
thing concerning our Salvation. 43^
Solar Spots.
SM, generate and diffolve in the face of the

SuadJJ; Opinions touching the Solar Spots. 3 9
An Argument that neceflanly proveth the So
/«rSp.ritog-nerateanddiaolve. 4

A conclufivc Dcmonftration to prove that the
Spis are contiguous to the Body of the

Sun. » I

The Motion of the Spns towards theCircum-

cumfcrencc ot the Sun appears flow. 4 1
The Fioureof the towards thcCircumte.

rence of the Suns DUcus , appear narrow,

^^^tTa^Spu arc not Spherical , but flat, like

thin plates. r- 1 a j ^

The Hiftoryof the proceedings of the Atadc-
mian for a longtime about the Oblervatioii
, of the Solas Spots. . ii • V r

A conceit that fuddcnly came into the mind ot
our Acadcmian concerning the great confc-
qucnce that followeth upon the Motion of
the Solar Spots. j -

Extravagant Mutations to be obferved in the
Motions of the Solar Spots forcfccn by the
Academ-ck, in cafe the Earth hadtheAnnU"

ai Motion. , ^ ...

The firft Accident to be obferved in theMof i-
on of the Solar Spats, and confcqucmly all
the reft, explained. . _ 3^

The events bcin- obferved were anfw arable to
the Prediaions touching thcfc S/^»;.v 3 1 S
Thouah the Annual Motion alligncd to the
Earth, anfwcrcth to the Phaenomena oi the
Solar Spots , yet doth it not follow by convcr-
fion , that from the Phenomena of the Spots
one may interre the Annual Motion to be-
lon^ to the Earth.
The PurePcripatetick Pbllofopbers will lau|h
at the Spots and their Ph.-enomena , as tnc
lulns^f the Chriftals in the T 1 e^
(cope.

The sV*-S/'«j of Galileo. 194

Star

an<l Stirs.

The Swi infinitely (ui paffc ihe lell of Heaven

It is ?a kflrimpotUble for ^>ar to corru^
thanthewholc TerrcftrmlG obe. 7

kva^^r^^^aSn^c^rt

AScSerimcntthatlhewcththecnereafe
n the S,L, by means oi the Adventu.ous

A S 'Jof the Sixth M»f if"^^J"PP°^'t^,]; J^s
cho and Schciner an hundred and Gx M-H^ns

of timesbiggcr than needs.
A common errour of all Aftronomers touclung
the Magnitude oi the Stars. sttMi

Venus rcr dcicthtlie fertour of Aftronomers
in determining the Magnitudes Stars in-
cxcufcable. ^. 3^^

Away to meafure the the apparent Diameter

Bydcpriviiig Heaven of fome Star, one might
come to know what inlluence it hath upon
us. . 334

Enquiry is made what Mutations , and m what
St. r.- , is to be made by means ol: the Annual
Motion oFthc Earth. 34^

The Sta>snQCicr to us make greater divcrfities
than the more remote . 34^

F I X

£ D

Stars.

Great difparity amongft the Motions of the
Particular Fixed Stars if their Sphere be
moveable. ^

The Motions of the F/W Stars would accele-
rate and retard in feveral times, if the Starry
were moveable, ' 102

The Probable Situation of the F/W St^rs. 299

Suppofing the Anniifel Marion of the Earth, it
fulloweth that one Fixed Star is bigger than
the whole Grand Orbe. . ^ 3^4

The apparent diveriity of Motion in the Pla-

. nets, is infenfiblc in the F/.WS/^r5. 325

Suppoling that a Fixed Staro.( i\rc Firll Ma;^ni-
tudc is no bigger than the Sun, the diverfi-
ty which is lo great in the PlanCts 5 is al-
moft infcnfiblc in the FixU Stars. 325

The Diameter of a Fixjd Star of thetirft Mag-
nitude, and one of the b'ixth 3^5

Thediftanccof a F/W Star of the Firft Magni-
tude , tl.c Star being (uppofed to be equal to
the Sun. ' ^ 3/^

InthcK'W Stars thedivcrficy of Alpca: caulcd
by the Grand Orb , is little more than that
caufcd by the Earth in the Sun. 3 - ^

The Coir.putation of the Magnitudc-of the
Fixe4 Stats in rtfp.a ot the Grand
Orbe. ' 3:^

The Apparent Diameter of a Fu-^i Star ot the
Fir ft Magnitude ^ not, more than five Se-
conds. ; ; *r . -

By ar.othcr Suppofition taken from Aftrono-
mcis , the diltancc of the Fixed St&rs is cal-
cuUued to be 10800 Semidiamcters of the
Great Orbe.

The place afllgncd xoafixid Star is much leUe
thmthatot' Planet. 335

The Mutations of the F/.W Stars ought to be
in fome greater , in others lelTer , and in o-
thers nothing at all. ^ 343

The "land Di'^^^^^^y Copernicus his Do-
" ' drine

arinc ; is that which concerns thcPnarno'^
menaof the Sun and Fixed Stars, 34>

TheFw^/S^^riin the Ecliptick never Elevate
nor Defcend , on account of the Annua!
Motion , but yet approach and recede. 545

The F/^^^ S/^r/wiihout the Ecliptick elevate
more or lefib , accordmg to their diftance
from the Ecliptick. 347

The Epilogue to the Phsenomenaof the Ftxea
Stairs caafed by the Annual Motion of inc
Earth. . 34i^^

A place accommodated for the Obfcrvationoi
theFAW Stars, as to what concerns the An-
nual Motion of the Earth.

New Star.

The greatefl and leaft Elevation of the
Star differ not from each other more than the
Polar Altitudes 3 the (aid Scar being in the
Firmament.

Steel.

SmI Burnifhed , beheld from one place appears
very bright , and ftom another 0 very ob-
kmc. ^

Stone.

The Sftf«^ falling from thcMaftof a Ship Hght^
in the fame place , whether the Ship move
orftandsftill.

Strength.

The Strey^gth diminifheth not, were it not cm-
ployed.

S U N.

The Sm more probably in the Centre of the
Univerfe than the Earth. :

Obfervations froni \% hence it is colle(5tcd that
the S/^« and not the Earth , is in the Centre
of the Cdeftial Revolutions.

The Sm and Moon encreale little by Irrad^
tion. • 3^

The.S///2itfclfteftifieth the Annual Motion t^
belong to the Eai di- I f

If ih2 Ekrth be immoveable in the Centre 01
theZodiack, there muft be afcribed to tnu
Sun four feveral Mouons , as is dech^i^^^^^^
length. 3-

The diftance of the Sun conteineih tweiv^
hur.dred and eight Semidianntas ^ ^»

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

The

i|jc Diamctci of the Sun half a Degree. 325
* he Apparent Diameter of the Sun hovr much

it is bigger than that of a Fixed Star. 325
An Example of Gods caie of Mankind , taken

from the S»«. 33 3

An cxqiiifite Obfervation of the approach and

departgre of the Sun from the Summer SoT-

The S«« pa(feih one half of the Zodiack nine
daycs fooner than the other. 41 e

The Miracle in Jofhuah of the Suns (landing
ftill anfwers not to the intent of lengthening
the day 5 but on the contrary excellently a-
grecth with the Copernican Syfleme. 45 6

The S«« without change of place revolvcth
upon its own Centre in the fpace of a
Moneth.

.The Nobility of the Sun as being the Fountain
of Light , Heart of the World , and Prin-
ciple of Motion, 45^

\The Suns (landing flill in Jolhuah explained by
Kepler. 462

*neS«»foundtQbe neererto us than in times
paft , by five thoufand Miles. 469

The Sun^ Moon, and Stars , are one and the

L fame thing. 485

^hy the Sun to our thinking moveth 9 'and not
the Earth. i^85

How the Sun is faid to rtfe and fet by extrinfick
denomination. 4^^

TheS«« is the King 5 Heart, and Lamp of the
W'orld.

Sympathy.

^/mfathy and Antipathy 5 terms introduced by
^hylofophers , the more cafily to give area -

57i

fonof many Natural Effeas.

System of CopcrnicHs,

Copemican Sjiftem onCe admitted for true
Expofitions might be found out for all thofe
^criptures than that feem to make againft

^^icus ^Stunica field that the Scripture may
he befl expounded by ..the Copernican Sj>^

468

^hc

The

System of Vni*verfe.
^jHem ef the Univerfe defigned from the

Talkie,

^ the Golden CandledickV Voo

PaSc/'^'''^^"'''^ likcwife by the Apple in
^ ^ ^^"^^ 501

1 ELESCOPE.

Tbe^ Telefc.pe. cnablcrh us to difcourfe better of
<-clcftialMurcrs than Anflotlehimfelf. 42

Invention of the Te/e/^oj^e taken from Ari
^otk,

An ingenious ConHderation about ufino of the
Te/^cope with as much facility on the KouncJ-
top of the Maft of a Ship, as on the Deck. 2 2 5

The Mutations made in the reltfc^pe, depend-
ing on the Agitation of the Ship. 226

TheOpcv arions of the 7^/^/?^?^^ accounted Fal-
lacies by the Peripatcticks. ZQAcrzig

The Telefcope is thebcft means to take away the

. Irradiations of the 5 tars.

The Telefcope hath much contributed to the Re-
Ifau ration of Affronomy.

Theology.

Iheolop the Queen of the Sciences, and where-
m her Prcroeative confifls.

Things.

Somer/>/if^/areof that nature, that their parts
may fcpcratc from one another, and from
their whole, others not. ♦ 49^

rhf os arc^fimply denominated in comparifon
of al! or thegreateft number of things of that

T H R

the Number Three celebrated amongff the Py-
thagoreans. \j

Tide.

The Tide and the Mobility of the Earth mutu-
ally confirm each other, -g^
Tjde. Vide Ebbing and Flowing.

True.

A '

.^Ppej

^arances.

rr/<fandFairarcone and [the fame, as aJfo Falfc

tjg,.'- 25?6 andDerormed^ uy

^J^m of the Untuerfemghx probably have For proof of True Conclufions . many folid
intended to nave been reprelented by Arguments may be produced , but to prove

Z 2 z a

the

The Table.

112. 245

afalfcone, none.

Truth, and Truths.
Untruths cannot be Dcmonftrated as Truths

The Truth fomctiracs gains ftrength by Con-

tradi«5tion. , • j-)- ^

rruth hath not (o little light as not tobe diko-
vered amongft the Umbrages ot tai-
ftioods.

T Y C H O.

The Argument of T^ch grounded upon a falfe
Hypothefis.

TKfc/aad his Followers never attempted to
fee whether there were any Phenomena in
the Firmament for or againft the Annual Mo-
tion.

Ticho and others argue asainft the Annual Mo-
tion , from the invariable Elevation of the
Pole.

Velocity-

Vniform Vefocitj futable with Circular Mo-

Nature doth not immediately confcrrc a de-
tertninate degree of ydoatj, although She

could ^ ^

Jh^relocity by the inclining plane eqi^al to the
relocitj by the Perpendicular, and the Mo-
tion by the Perpendicular fwifier than by the
inclining plane. . c

Vehdtiu are {aid to be equal , when the Spa-
ces pafTcd are prpportionate to their
times. ]^
The greater Velocity e^adly compcnlates me
greater Gravity.

Venus.

The Mutation ;of Figure in argueth its
Motion to be about the Sun. ^ ^95

Veuus very great towards the Vcfpertmc Con-
junaion, and very fmall towards theMa-
tutine.

yenus necelTarily proved to move about the
Sun.

The phaenomena of Venm appear coiitrary to
' the Sytoi^ ^<^P^^"icus. 3°^
Another Difficulty taifed by r«»«/ againft Go-
pcrnicus. 3^^

re^Hs according to Copernicus cither lucid i
it fclf , or a tranfparent fubftancc. V
The Reafon why V€rm and Mars do notap
pear to vary Magnitude fo much as isi^^

A?ccond Reafon ofthe fmall apparent cncrealc

ot Venus, m de-

Vcnus renders theEneurof Aftronomcrs in u
termining the Magnitude of Stars incx

cufeable.

Of the Motion o;
Water,

3*7

V U. S S E L.

Water in a y^^*^

Und.e rs t AND , €^r.

Man Underjlandeih vciy m\Kh mitfiyu,

little exienfm, . ■

Humane Uuderftanding operates by->Ratio^^

nation. *.

U N 1 V K RV S

The Gonftitutionof/ihc ftul^'fi"^^^"^
Nobleft Problems a Man can-fittoy-^ '

The Centre of xhz 'mvirfe ^
ftotlc is that Point about % ^
ftial Spheres do revolve^ . c .

Which ought to be accounted the .^phcrv^

x}cic Univerfe. • o \

It is a great ralhnelle to cenfure that to n^ * .
perfluous in the tlmverfe which we ^ ,
perceive to be made for us.

V UR*ST i^t 1 U S.

Chriftianus VurftHim read certairt Leftui^j
touching the Opinion of Copermcus, ^
what happened thereupon.

,10

Water-

He that hadnot heard of the Element of
coold never fancie to himfelf Ships ^

(hcs. A-^^nf^r^J"

An Experiment td prove the Reflection ^ ^
«r left bright than that ofthe Land.

The Motion of the r^^^r in Ebbing i^i^^

ing, not interrupted by Reft. ^^^d

The vain Argumentation of fomc , ^L^^^
the Element of mur to be ot a

Superficies. ' " -fijC

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

The Table:

he Pi-osrcffive and uneven Motion makes the
trater in a Veflel to run to and !ro. 5X7

may make the coiitcined iVMr to ale and

A^^rnm in one end of the Veffel re

tnrncihit fclfto.£H'^'^'«f; . rf/.^
InSoiterVcflelsthcUndulattonsof^.-

ter, are more frequent. Unduhti-
Thc greater profundky m^keth the VnduUn

O Jof »ra£r the more frcqu...t.
Why in narrow places the Courfe ot

«»« U fwifter than m larg,er. 3^"

Motion of Heaven. ^

VV E I G H T S-

Itsqucftionable whether. Dcfceading ^./^^^^^^
move inaRightLine.

in time ,
Moment
(ent.

the Dlvim n'jfdonj rcfolveth in a
, that is hath them alwayes pre-

I T.

The mt of Mai admii ably acute;
ThcPufilanimity of Popular WiH'
Pocdck m'ifoi two kinds.

W o R L D.

364

world. Vide Unherfe.

The mrlds parts arc according to Ariftotle two,
Cckftialand Elementary, contrary to each

-Xhcmrld fuppofed by the Anthour [Gahleo]
to be perfeftly Ordinate. lo

The Senfible World, 96

It hath not been hiihcrto proved by any whe-
ther the H^or/J be finite or infinite. 29^

If the Centre of the fVarld be the fame with
that about which the Planets move, the Sun
and not the Earth is placed in it. 29^

West.

The Courfe to the r./? Indians cafie, the re-
turn difficult. ^

W I N D £•

Conftant Gales of IVinde within the Tropicks
f blow towards the Weft. 4^^
' mndiS from the Land , make rough the
Seas. ^
Wis DOME Pi'J'i^^-
tMr^iWifdme infinitely infinite. ^5

I T I N G.

Some Write what they underftand not I and
therefore underftand not what they Write, 63

The Invention of Writing Stupcndious above
all others.

Year.

The Tears beginning and ending, which Ptolomy
and his Followers could never pofitjvciy af-
fign, is exaaiy determined by the Coper-
nican Hypothefis, 4f?

THE END OF THE tABLE.

Early European Books, Copyright © 201 0 ProQuest LLC.
Images reproduced by courtesy of the Royal Library, Copenhage
2°K.B. 9,163

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

MATHEMATICAL

COLLECTIONS

AND

TRANSLATIONS:

THESECOND

T O M E

THE SECOND PART>

Containing,

/ p. BENEDlCTUsGASTELtUS,fe 'X)/SC0^2^5£

'of the me^su\Ario:Ni of ^u:j\c-

11 m gemtemcal "DEMO ^ST^i/riO :^CS of
theMeafureof ^UNNi:AC.g IFAtE^S.

III. m LETTE'^S and QO I'D E^JTlOU S

touching the draining of FENNS, Dinerjiom of
1{1VERS, &c.

IV. D. CoRsiNUs, His 'l{e LJTWN of the jlateofthe

Jnmdations, &c. in the Territories of ^OLOg^J ,
andVE^KK^K^'

- By THOMAS SALUSSU'R.r, Efq.

LONDON,
Printed by William Leybourne, ivfDGLxi.

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

OF THE

MENSURATION

O F

RUNNING WATERS.

An Excellent Piece
rrritten in in LI A

B Y

DON BENEDETTO CASTELLI,
Abbot ofSt.^BENEmrro JLOTSW,
and Profeflbur of the Mathematicks to
Pope U%pAN VUl in ^OMf.

EngliOied from the Third and beft Edition, with
die addition of a Second Book not before extant:

Printed by WILLIAM LEYBQURN, t66t,

A a a a 3

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

THE

AUTHOURS EPISTLE

T O

Pope VRBAN VIII.

T av at the Feet of your Ho^
^ " lineflfe thefe my Confide-
rations concerning the

Mensuration -Ob
Running Waters:
Wherein if I Ml have fucceeded , being a
matter fo difficult and unhandled by Wri-
tersboth Ancient Modern , the dUboveryof
any thing of truth hath been the Effea of
Your Holineffes Command , and if through
inability I have mifl-ed the Mark, the fame

€ f Com-

Command will ferve me for an Excufe with
Men of better Judgment , and more elpeci-
ally with Your HolinelVe , to whom 1 humbly
proftrate my felf , and kiffe Your Sacred
Feet.

From ROME.

Your Holincffes

tJUofi humiU Strvtt

BENEDEttO'

A Monk of C^""'

A N

C C O U N T

O F T H E

Authour Work.

ON BENEDETTO CASTELLI,
the famoHS Anthour of thefe cnfmng
VifcoHrfc! of the Menluration ot
Running Waters, h defcended from
the WorjhipfKl ['AMlLr of the
C ASTELLll , and took, ha
iirii breath near to the TH R A-
5 i M £ N 'L' SX^^>'>'^ Hanibal gavs
a fatal overthrow to the Roman
Liiions ■)in that fweet and fertile part
1^^^^^^^ of happy IT hhY, called ffce Territory

V pre/.«r/«t-«-'^ , „ere ..re

^"V'f Iw.f KT/L obfer^ant of the Fropenjlonof

X-''r"idTaidhtl 'according L the Delouon of that Conn-

try) ,0 the Servue of the Church ; onA^'- d h . .

np^ .order of Black- rur ' -'/^^ /^g.^ia.nes. N.-

0/ Monte Call no , frttl Jrom tje . . „f fc,, fa-

tnre , that She '^'^^^^^''^f"'''':^^^^^

.ours upon Inm , fent htjn ''^ ' J ^ C.l all Ktnd/of
ennobled and ,M.unated mth L ^ ^ ^^^^.^^ ^^^^
literature, that hardly any Cent ur)

the like. . y

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2°K.B. 9,163

An Account Of

In f articular, the SCIENCES MAT HEM ATI-
C A L had then got that Fame and Efteem in the Learned World,
that all men of Spirit or Qnality became cither Students /»5 or
Patrons of thofe Sublime Knowledges. On this occafion the Curt-
ofity of our AU T H O U R being awakened , his ABi<ve Wit
could not endure to be any longer confined to the Slavip Tuition
of Hermetical Pedagogues but in concurrence with the Genius
of the Age , he alfo betoo^ him f elf to thofe moji Generous and
Liberal Studies. His helps in this his deftgn were fo many^ and
fo extraordinary , that had his Inclination been weaker , or his
Apprehenfton hffer , he could hardly ha*ve failed attaining more
than a Common Eminency in thefe Sciences. For befides the D<^'
luge of Learned and "Vfefnl Books , which the Preffe at that
time Jem forth from all parts E U R O P E , he had the good
Fortune to fall into the Acquaintance , and under the Injiruclion
of the moji Demonjlrati<ve aud mojl Familiar Man in the World,
the Famous GALILEO : whofe fucceffe being no lejfe u{on
this his Pupil than upon the reft of thefe lllnflrious and Ingeni*
OHS Perfons that reforted from all parts to ft under his Admi-
rable LeBures , he in a fhort time attained to that Name in the
Mathematickj , that he was in*vitzdto ROME, Complement
ted, and Preferred by his then Holinefe the Eighth URBAN,
upon his 'very firjl Acceffion to the Papacy , which was in the
Tear 1633.

This Pope being moved with a Paternal Pro<vide/ice for the
Concerns of his SubjcSis in that part (?/ I T A L Y about B O'
LOGNA, FEKRARA,WCOMMACHIO, /y-
ing between the Ki<vers of PO and RENO, which is part of
Lo Stato (lella Chiefa , or the Church Patrimony , appoints this
our CASTELLl intheTeari62i^, to accompany the Right
Honourable Monfignore GORSINI {a moft obfervant and
intelligent perfon in thefe affaires , and at that time Superinten-
dent of the General Draines , and Frefdent (;/ R O M A G N A)
in the Grand Vifi tation which he was then ordered to make con-
cerning the dif orders occafioned by the Waters of thoje parts .

f CASTELLl, hailing now an Opp criuiitty to employ,
yea more , to impro've fuch Notions as he had imbued from the
LeBures of his Excellent MASTER, falls to his work. ^^^^
all indujiry : and in the time that his Occafons detained him i^
R O M A GN A he perfeSed the Firft Book^ of tlm his Vif'
courfe concerning the Menfuration oi Running Waters. He con-
feffeth that J)e had fame years before apply ed himf elf to this P^^^
of VraSiical Geometry , and from fe^jeral Obfer^ations coUeSed
part of that DoSlrine which at this time he put into Method , and
T^hich had procured him the Repute of fo much SkjU that he began

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

The AuthOur And WorK;

to be Courted by fnndry Princes , and great Frejates. In farticH-
lar about the begmmng of the Year ^62^. and before h^lnrnta-
*• , R r» ivl F he was employed by Prince Ferdinando I, Grand
T, ??USC ANY , LenJythe Viforders M> at that
t^lJenl uttU Valley of .n the Me.do.s that lye

r ; K .,/.r nf Serchio and F ume Morto : and in the pre-
7Ze ffTctfdDt, GrandVn.heffeU.ther ..he Comntf
Toner! of Server. , and fnndry ether ferfon. ^ f'^hour^
LZe fo great a progrefe ,n that af air as gaje h. Moft Serene
mJJihigb fltisfa^^on, and gamed himfelf n,.ch Honour.

fooner had he in his fore- mentioned Voiage to R O-
MAGNA (tfhich was hit fen> Moneths after , m the fame
Tear-, committed hk Conceptions to paper , but he communicated
thej to certain of his Friends. In M number we finde S^gno-
re Giampoli S cretary.fthe Fopes?ri.ate A§aires- whom in
the be^Lng of the Firji Book he gratefully acknoMgeth to
TJXeTL ributaryiin his Purle , towards defraying the
1 If Experiments, and in his Pcrfon, towards the debating

T iltTnlZf Arguments upon thisSubjeB. Some few year,
andcompleatingo; ytrg t

J ftllWef -'itb a Treatife of the Geometrical

IZn of his whole X^o^rine. What Reception it found

7ferZd{ow Hovdty and Facilicy conjunBion with Vcnty
J^l,, „ Charm of irrefiliable Operation.

f n.TZisJo!thatn:manbcfore hint had c.er attemp-
JtTilnflrateaU the three Dmenfions *o wtt the Lengthy
Ladth and Profundity , thts Fluid and Current Ele-
Tent And he LeBeth fuch groffe Erronrs ^"^e few that
. / utjnn the SubieSi (of which he inftan'

had untertook to '-"^ "f ^; f as tlofe that include

;V'TrTrl?/^S "^^^ -'heaLfParado.es (for /o

^'''^'Frfie?H//l"«.,/e and True ; and that upon fo Familiar
r^- V \ndMan fe(l Demonjlrations , that Iha'^e oft que-

ftioned wtth myje j Argument before him

dijco'vertng , or ail ' . n p^.n^ty and Infal-
fornotdifco^eringaDo^rt^fJ^^^^^^^^^^ y ^^^^ J^^^

libiUty. But yet as if ''.^^f ;S„7 i feleBs aSubjeB that
World to him byfo excellent '^J^f^; ^^er Souls, upon

he knew ^"M^^^'llff ^indbyaUUaJk,nd tn General, as
the accounts afore-named , anavy au

iratifying them tn their much adored Idol Utility, And to ren^

An Account Of

4er his Art the more profitable^ he rednceth the lofty ^ and e a fie- to-
be-mijiah^n Speculations of the Theory , into certain and facile
DireBions for PraSiice j teaching us how to frequent and repaire
the Breaches of ^eas , and Inundations of Ki'vcrr to drainc
and reco<ver Fenns and Marches 3 to divert , con^veigh and di-
flribute Waters for the FlorJing and Stercoration of CroHnds^
Jirengthening of Fortifications ^ ferz'ing of Aqnadu^is ^ prefer-
ring of Health (by clean fing Streets^ and fcorvring Sewers ) and
tnaintaining of Commerfe (^ by defending Bridges ^ cleering Ki'
*vers , and opening ?orts and Channels') with innumerable other
Benefits of the lih^ nature. A^d^ that i may omit no circittnftance
that may recommend my Authour , the Fortune of this hisTrea-
tife hath been fuch ^ that as if he intended a Plus ultra by ^^
or as if all men defpaired to out-do it ^ or lafily^ as if C A*
S T E L L I hath been fo great a Maftcr that none ha^c prefa-
med to take Pencil in hand for the fintjhing of what he Pouf-
foild, this fmallTraB lik^ethe Arabian Phoenix (^of which it is
faid Unica femper Avis) did for fe<veral years together continue
fingle in the World , tiil that to <Lferifie it to be truly Phoenician,
it renewed its Age by undergoing a Jecond Impreffion. And as if
this did not make out the Immortal 'vertue of it., it hath had
Anno 1 660 a third Circulation , and rifen in this lafi Edition as
it were from the Vme of its Authour 5 and that fo improved by
the Addition of a fecond part , that it promifeth to perpetuate
his Merits to all Fofterity, To be brief the meer Fame of this
Work refounded the Honourable Name of C AS T E L L I lit'
to all the Corners vf Italy , I may fay of Europe 3 infomucbj
that^ in hopes to reap great benefit by his Art , the rcfpeSii'Z/e
Grandees of the adjacent Countries courted his Judgment and
Advice about their Graining of Fenns , Y^ivcrfion of Ri^vers^
E'Z/acuation of Ports ^ Pre<venting of Inundations^ d^c. So that
every Summer he made one or more of thefe Journies or Vifitati*
ons. Particularly^ the Senate of Venice conjulted him about their
Lake 5 to whom he delivered his Opinion in May 1641 . and up"
on farther thoughts he prefented them with another Paper ofCon*
federations the 20 December following. Prince LEOPOLDO
(?/ TUSCANY likewife requeued his Advice in the begin-
ning of the enfuing year 1642 , which occaponed his Letter to
Father Fiancefco di San Giufeppe , bearing date February i>
To which Signore Bartolotti oppofing , he writes a fecond Let-
ter 5 directed to one of the Comniiffioners of Sewers , vindicating
his former , and refuting Bartolotti , both which I here gi've

yoiu

§. The Preferments which his Merits recommended him untOj
rverefirfl to he Abbot of Caflino , fnfm which he jrjs removed

Anno

The Authour Amd Work.

Aiino 1640, or thereabouts , unto the Abbey of Santo Benedet-
to Aloyfio -, and mnchaboHt the fame time preferred to the Dig-
nity of Chief Mathematician to his grand tatron Fope URBAN
VlII. and PHbliiue Profeffour of Matbemattcks in theVni-

t-ertf/y 0/ R O M E. , ^ . ^ , • c ' V ji.

i Here a Stop was put to the Carter of hfs tortuniv ^ Mdbe-
ina fntter of Honour than of Years , tpos by Death, the Importu-
nate lutreriper of Generous Deftgns, pre^nted rn doing that
farther Good which the World had good reafon to promt fe itfelf
from fo Profound and Indujlrious a Perfonage , leawHg many
Friends and Vifciplcs of aU Degrees and Qualities U Imettt
hkloh, and honour his Memory.

6 His Angular Virtues and Abilities had gatneA him the
friendjhip of mry many ; as to infiance in frme , he haixon^
ttaSied arid Amity wUh Monfignore MafFa Barberino a Floren-
tine, Procfe^ofthePttbliqueWayes, and afterwards Pffpe mtb
the Name of U RB A N V r I i. was faid before ; with the
*bo^,.named Monfignore CorCmi SHpenntendantof theGt«eral
Draines : with Monfignore Piccolomini Arch-Bijhop < Siena f
roith Cardinal Serra : with Cardinal C^pom. who i>*^>M-^
mch and writ weU upon this Subjf, and with Cardinal C^c-
ta„« ifeo frequently confulted with him in hfS defign of Dratn-
iTtZ Finns of R O M A G N A. Moreo-ver ?nnce L E O-
PO L D O , and bis Brother the Grand Dwh bad very great
kindnelTe for hHit; which f peaks no fmaU alWamotis tn htm ,
eonftdering him as a favourite of the Family of Barbemu , be-
tjen whom and the Houfe of Medeci there ts an inveterate
Fcwd. Amongfl perfons of a lower Osality he ^cknowledgeth
Sbnore Ctampoli the Popes Secretary , Sig. Ferrante Cetarini,
si Giovanni Bafadonna Senator of Vcmc^; and 1 find mem.-
S Sig. Lana , Sig- Albano , Padre Serahno, Pad. Francefco
deSan Giufeppe, W**'*";""^^*-^- „. ,. ^

TrheWorls in which he will furmve to aU fnccecding Ages
ariarH His foM and fober Confutation of the Arguments of
SiLore Lodovico dell Columbo , and Signore Vmcenno d,
f\^Z\oainli tbeTraB of Galileo Delle cofeche ftanno fopra

tbTrutors -very rarely reap from the pains they takf m Culti-
vating Zr^^^^^^^^ -This Apology was frft Primd A^^^^^^
.nlL afecind time t'^^^'Pji^,'", f/'^'f
nifts, amoiigji the Work/ »f P ^}:}^ > If f/lTok^^
darned Viviani 1^56. He bath Uh^aife writ federal other
cur ous Pieces , la»t informed by the moft Conr^eo-s C^roio
Manoleffi of Bologna amongfl others an excellent Ire attfe
cZrning Colours, M be putteth m .n hopes to fee printed

/An Account Of

very fpeedily. And laft of aU thef^ Difcourfes a>id KefieBions
upon the Menfuration of Running Waters , with the addition
a Second iBook^, three EpiftleS y and foiir Conftderationi t^^^
the fame Argument^ which candHqe ntuch u ^
Brine and Facilitate the PraBice of it \ and fp^hich wi th a Ke/^-
tionvf Monfignore Corfiui , mai^ethej^ecand part of fj[ r fj^

u ,fHight here fally forth into, the CitaHon of [i^^dry A^-
thorns of Good Account ^ that h^tve tranimihed^^
to Ppjierity , hnt /ball confine my felf to anely jwo'^ the om i^
ofhis\ Mafter , the other of his Scholar ti)^n whom ibere can-
not be two more competent Judges of hii j^cfomplifiments*
ttgifLwith his Mafter, the Quick-fight e^d^^ 4nd truly Lynaan
GAL I L E O , r^ho Jpeal\ing of bp Abilities in Aflronomy faith
(4i)NclUcontinu- (a) Chela telicica del fuo iugegno non Ja f a biiognoia dell' o-
^"fidcrit P^^* "^^^ ^^^^'^ > fubmitting a cert din Demo^ft^^^

which he intended to divulge^ to the Judgment of ibis our Abbatjxc
(*) Imtn al P. writei to him in this manner : (f?) .Ciiicfto jo cctfu Ulrica ^ Sl- S'
^TJa^c'^^o' P^^ i^ttctd. prima che ad alcim altrp , coi^ a^tf i^Uerne prm
li. ^. Dcccmb/mente il parer fuo , e doppo quello de npftii Amici difcpft^^
cQnpenfiero d* inviatae poi altre Copie ad aitLi,AiT^ifV^ l^^^*'
€ di Francia, quando io ne venga da ki coufigliato : e qui prc-
gandola a farci parte d' alcuna deUe fue pcr^gfinc fpeoiUtioni i
con finccriflimo affetto, Sec. And' the mofi^^cuteMaihematfC^a/^
Signore Evangelifta Terricelli , late Fropffqiir to the drand
L>Hl{e in immediate Succeffion after G A L 1 L £ O , ma\cthfhis
(e) Dc Motu A- Honourable and Grateful Mention of him^ and his Boo\^: (^c) O
qoamm. mitto oiagnum ilium nutantis Maris motum^ Praetereo ctia®

«)p'37*P** omnem Fluminum , Aquarumque Currentiunitiim uncnfiiriini,
turn ufum 5 qnarum omnis doftrina repcrta primism fuit ab
Abbate BFNEDICTO CASTELLIO Preccptorc
, mco. Scripfic ille Scicntiam fuam, & illam non folum deicnaiiftra-

tione , verum etiam opcre confirmavtt , maxima cum Princi-
pum & populorum utilitate , majore cum admiratiopc Fbylo'
fophorum. Exut ilUuB Liber ^ yere aureus. | •

2 ha've onely two particulars more to offer the ^ffglfjk^^^
der : the /one concerns the Bool^y and it is this , 7h»it after the
general Aprohation it hath bad in Italy, I cannot but thin^it
defer^eth the fame Ci'z/il Entertainment with us , inregardihat
it Cometh with noleffe Novelty, Facility, Verity, andUcifity
us thantothofe whom the Authour favoured with the Origtttal.
Our Kilmers and hewers through Publique PiJlraBigai and Pri'^
^att buroachments are in great dif order , as thofe Channels for
^'^fiance which formerly were Navigable unto the very Walls of

York

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2°K.B. 9,163

The Authour And WorK,

York ami Salisbury, &c : Our Ports are choakcdand chftrM
by Sbelfes arid Setia>n'>ts : Onr Fen^sdo i,y great fart he ^ajic
Iduninpo'ved: Nor. all thcfe ,«ay be (a.d ^^l/"^h *be
ConfeffJ of [onn r^hofe Miies upon the Copy of the F r^
Boiko>,eh of our A«thour hath got tr,em both Money and Repn-
Utiort, in part ha'v.e been) remedied by the Way, and Means ho
here fets down. The truth is the Argument hath been f afl over
^,th an Vm'verfalSdence; fothattothtsday lhajenot feen
.ny thingthathathbeenmitten Vemonfiratt'vely and r.ttb Ma-
thinatical Certainty concerning the fame fave onely what
learned Frelaie hath deU-vered of ns Ow^' Invention in t^^^^^
TreatiCes: rvho yet hath fo fully and plainly handled the WhoU
hoSirtne that I may affirm his fVork.to be e<v<ry way abfolnte It
Zfeclfcji the Delnjlration of theSecond Tropofuon of the
sZnd Bolididnotr^eipleafetheAnihour ^^idhadheUji
he r^onld ha've fupplyed that defeB. , but being prevented by
iZh Z KeiderLfi content himfelf with the Mechanical
Cofthat U gi^cih yon of the truth of fo E.ceUent a Con.

''Trhe other particular that I am to ofer is, that out of my
firL contribute what lyeth in me to the compleattng of th, Fiece
fl vll tFraBice , / have exeeded my promife not onely ingi.
i:^; le7:^and following Books M were not e.tant at
xZMme oftendnng my Overtures , but alfo in that I have added
a Mapor?latof aUthcKivers, Lakes, Fenns, &c. mentioned
thoroLut the Work. And if 1 ha^c not keft ^.^fy^f^
Hme , let it be conf.dered that lam the Iranflator and not the
friner. to conclude, accordingto your acc^tance "f fhef. my
endeavours , you may eyfeB fome ether Ms of no lejfe Profit
and Delight. Farewell.

r. s.

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2°K.B. 9,163

ERRATA of the /ert?//^ Part of the firji TOME.

Page 2. Lini 25,/<?r muft rM/^much. P.3.1.2 2,r.andlet.l#2j.r.watcr5from.l.4^*
r.Tappe, (as eviry wku elfe ), Page 4.1.i8.r cords, Pagc6.1.p.r.acquire,or.
Page ^.I.i. r. irrcpcrablc. P.io.l.i 3.r.diffimboguement. ¥cr Page i7.r.P-i5«
V,i'y,\.i'j^r,mA,^6,r:yszs,ll%,r.Panaro, V.ijA.liyGiulU. I ly.r. Mcafurcrs.l.
ijj/.mcafurcditj.r.neceflarily. P. 23. 1,19. r.for help. /orVa^e ^1 .r.^ *3^*^''\^'
p,3 1.1.3 2.r.Soe.p.4i,L2o.r.to line.p.48J.i9-^-us theMd. FignrtfiV^i P'^}*
1.30^ and 3 Theorem r.Propofition. p.53.1.29.r.again. P.57.I.1P5 Mameir.
l,44.r.bodily. p.58.1.p*r.gathering.l.40.i?w/V5.p.6o»r.2.iw//5 if. p.
if^/i? p.66 .1.3 5 . r. Stoppage of. p.68.1. 1 2, f<;r Lords the r. Lords. 1 .ult.fonh^y
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^.pa 14* p. 1 14 J.3 5 .r.of aoo.].4i.r.clofed p.i 1 5 .1.29.r.conftant5.

O F T H E

MENSURATION

Running Waters*

LIB. I.

Hat, and of how grclt moment the confix
deration of Motion is in natural things,
is fo mahifeft , that the Prince of Ferj-i
pateticks pronounced that in his Schools
now much uled Sentence : Ignorato wp-
tu , ignoratur natura. Thence it is that
true Philofophcrs have fo travailed in the
. contemplation of the Celeftial motibna^
and in the fpeculation of the motions of
Animals , that they have arrived to a wonderful height and fub-
limlty of underftanding. Under the fame Science of Motion
is comprehended all that which is written by Mechanitians con*
ceining Engines moving of themfelvcs , Machins moving By the
force of Air , and thofe which ferve to move weights and im-
menfe magnitudes with fmall force. There appertaineth to the
Science of Motion all that which hath been Written of the
alteration not onily of Bodies , but of our Minds alfo , and
in fum 5 this ample matter of Motion is fo extended and di-
lated 5 that there are few things which fall under mans no-
tice 5 which are not conjoyned with Motion^ or at leaft de-
pending thereupon , or to the knowledge thereof dircfted 5
and of almoft every of them 5 there hath been written and
compofed by fublime wits , learned Treatifes and Inlirudiom.,

B b b b And[

Of ti&^ M ENS II R A t I 01

And becaufe that in the years paft I had occafion by Order of
our Lord Pope Vrban 8. to apply my thoughts to the motion

difficult, moft

rtant, ai

of
nd

the Waters ot Hivers^ (^a matter
little handled by others) having concerning the fame oblerved^
fome particulars not well obferved, or coiifidered till now, but oi
great moment both in publick and private affairs , 1 have thoiigMt
good to publifli them, to the end that ingenious fpirits might
have occafion to difcuffe tnor.c .9caaiy tlien hitherto hath been
done, fo neceffary and profitable a matre/, and to fupply alfo my
defeas ijo^ this fliort and difficult TraGtaj&e,r-%Diflic^lt^^^^^^^
thetrulh the ie knowledges, though ot tjrifigs rickt biir fenlH
are fometimes more abftruce and hidden, theh the knowledge ot
things more remote , and much better, and with greater exquifit-
nefs are known the motions ofthe Planets , and Periods of the
Stars, than thofe of Rwei^s and Seas : As that fingulai light of
PhilofopW^ of our times, and my Mafter Signorz Galileo Galilei
wifely obfervech in his Book concerning the Solar fpots. And
to proceed with a due order in Sciences, I will take fome fuppo-
fitions and cognitions fufficiently clear ^ from which I will after-
wards proceed to tke deducing oS the principal conclufions. Biit
to the end that what I have written at'the end of this difcourfc in
ademonftrativeand Geometrical method, may alfo be under-
ftood of ^hpfe which jiever ha)ve;applyed their thoughts to the
ftudy of Geometry , I hav eeiidoaivoured to explain my conceit
by an example , and with iheiiconfideration of the natural things
themfelv€[8{, muft after the famq order in which I began to doubt
in this matter 3 and have placed this particular Treatife 'here in
the begifining 5 adverting neverthelefs, that he who defiresmorc
full and abfolute folidity ofReafons, may overpafs this prefatory
difcourfej^nd onely confider what is treated of in thedemonftra-
tions placed towards the end,and return afterwards to the confi-
deration of the things coUefted iii the Corollaries and AppcndiceSi
which demonftrations notwithftanding, may be pretermitted by
him that hath not feen at leaft the firft fix Books of the Elements
of EugU0 i fo that he dihgently obferveth that which fol«
lowetb. .

I fay therefore , that having in times paft , on divers occafi-
ons heard fpeak of the meafures of the waters of Rivers , and
Fountains, faying, fuch a River is two or three thoufand feet of
watery fuch a fpring-water is twenty, thirty, or forty incheSj^^"-
Although in fuch manner 1 have found all to treat thereof in
word and writing , without variety , and as we are wont to fay,
^o^'^fiantifermone^ yea even Artifts and Ingeneers , as if it were
a thing that admitted not of any doubt , yet howfoever I f^'
ma)ned ftiU infolded in fuch ati obfcurity , that I well knew I wn-

derftood

Hb.u Running W aters.

derftood horiiiiig at all , of that which others pretended full and
clearly to undcrftand. And my doubt arofe from my frequent
obfcrvation of many Trenches and Channels , which carry
water to turn Mills , in which Trenches , and Channels, the
water being mcafured, was found pretty deep ^ but if afterwards
the fame water was meafurcd in the fall it made to turn the
Wheel of the Mill? it was much leffe, not amounting often to thb
tenth part, nor fomctimes to the twentieth, infomuch , that the
fame running water came to be one while more,another while lefs
in meafure,in divers parts of its Channel, and for that reafon this
vulgar manner of meafuring running W:iters,as indeterminate and
Uncertain, was by me piWy fufpefted, the meafure being to be de-
terminate, and the fame. And here I freely confelTe that 1 had fin-
gular help to refolve this difficulty from the excellent & accurate
way of difcourfing , as in allother matters, fo alfo in this, of the
Right Honourable and Truly Noble Signior Ci^;^p(?/i,Secretary
ot the Popes fccrct affairs. Who mo eover,not fparing for the cofts
of the fanie,gcncrou(ly gave me occafion a few years paft to try by
exaa experiments that which paft concerning this particular. And
to explain all more clearly with an example ^ we fuppofe a Veffel
filled with Water, as for inftance a Butt, whichis kept full,though
fiill water runneth out, and the Water run out by two Taps equal
of bigneffe, one put in the bottom of the Veflel , and the other in
the upper part ^ it is ma nifeft that in the time wherein from the
upper part (hall iffue a determinate meafure of water from
the inferiour part there (hall iffue four, five, and many more ai
the fame mcafurcs , according to the difference of the height of
the Taps , and the diftance of the upper Tap from the Superfici-
es and level of the water of the Veflel : and all this will alwaycs
follow y though, as hath btcn (aid, the Taps be equal , and the
water indifcharging keep the faid Taps alwaycs full. Where firft
we note, that, although the meafure of the Taps be equal, never-
thelefle there ifliicth from them in equal times unequal quantities
of water, And if we fliould more attentively confider this bufi-
neffe , we fliouId find , that the water by the lower Tap , run-
neth and pafTcth with much greater velocity , then it doth by the
upper , whatever is the reafon. If therefore we would have
fuch a quantity of Water difcharge from the upper tap , as
would difcharge from the neathcr in the fame time, it is plain,that
either the upper Taps muft be multiplyed in fuch fort, that fo
many more Taps in number be placed ibove than below, as the
neather tap fhall be more fwift than the upper, or the upper Tap
made lb much bigger than the nether, by how mdch that Ije-
neathfliall be more fwift than that above 5 and fo then in equal
times,the fame quanti ty of Water ftall difchairge from the upper,
?s dothfr jin:h e neather part. B b b b 4 t

Of the M EK S U ]R A T I o K J^i^' ^'

I will declare my felf by another example. If We fliould ima-
gine, that two cords or lines of equal thicknefs, be drawn through
two holes of equal bore ^ but fo that the fii ft pafs with quadruple
velocity to the fecond : It is mamfeft, that if in a determinate
time, we lhall by the firft bore have drawn four Ells of the line,
in the fame time, by the fecond hole we fljall have drawn but one
Ell of cord onely j and if by the firft chere pafTe twelve Ells,then
through the fecond there {hall paffe onely three Ells and in
ihort the quantity of cord (hall have the fame proportion to the
cord, that the volocity hath to the velocity. And therefore we
defiring to compenfate the tardity of the fecond cord, and main-
taining the fame tardity to draw through the fecond hole as much
co:d as through the firft, it will be neceffary to df aw through the
fecond bore four ends of cord ^ fo that the thicknefs of all the
cords by the fecond hole, have the fame proportion to the thick-
nefs of the cord which paffeth onely by the firft, as the velocity
of the cord by the firft hole hath reciprocally to the velocity of
the codrsby the iecond hole. And thus its clear, that when
there is drawn through two holes equal quantity of cords iB
equal time, but with unequal velocity, it will be neccflary, that
the thicknefs of all the four cords flia 11 have the fame reciprocal
proportion to the thickneis of the fwifter cord , that the velo-
city of the fwifter cord hath to the velocity of the flower- The
which is verified likewife in the fluid Element of Water.

And to the end that this principal fundamental be well under-
ftood, I will alfo note a certain obfervation made my me in the
Art of Wyer-drawing, or fpinning Gold, Silver, Brafs, and Iron,
and it is this j That fuch Artificers defiring more and more to
difgroffe and fubtillize the faid Metals, having wound about a
Rocket or Barrel j the thread of the Metal, they place the Roc-
ket in a frame upon aftedfaft Axis, in fuch fort that the Rocket
may turn about in it felf j then making one end of the thread to
paffe by force through a Plate of Steel pierced with divers holes,
greater and leflcr, as need requireth, faftning the fame end of the
thread to another Rocket, they wind up the thread, which paf-
fing through a bore Icfs than the thickneffe of the thread, is of
force coiiftrained to difgroffe and fubtillize. Now that which is
intenfly to be obferved in this bufinefs, is this. That the parts oi
the thread before the hole, are of fuch a thickneffe , but the parts
of the fame thread after it is paffcd the hole, are of a leffer thick-
nerffe : and yet nevertheleffe the maffe and weight of the thread
which is drawn forth, is ever equal to the maffe and weight of the
thread which is winded up.But if we fliould wellconfider the mat^
ter, we fluould finde,that the thicker the thread before the hole is,
than the thread paffed the hole, the greater reciprocally is the

velocity

Of Running Waters:

-velocity of the parts.of the thread paffed the hole, than thevolo-
city ofthe parts bf fore the hole: Infomuch that if ^grbi gratis
the thickneffe of the thread before the hole, were double to the
thickneffe after the hole, in fuch cafe the velocity of the parts of
the thread paffed the hole^ fliould be double to the velocity of the
parts of the thread before the hole i and thus the thickneffe
compenfates the velocity, and the velocity coropenfates the thick-
neffe. So that the fame occurreth in the folid Metals of Goldj
Silver, Brafs, Iron, &:c. thateveneth alfo in the fluid Element of
Water, and other liquids, namely, That the velocity beartth the
fame proportion to the velocity, that the thickneffe of the Me-
tal, or Water, hath to the thickneffe.

And therefore granting this difcourfe, we may fay, that as of-
ten as two Taps with different velocity difcharge equal quanti-
ties of Water in equal times, it will be neceffary that the Tap
leffe fwift be fo much greatei*, and larger, than the Tap more
fwift by how much the fwifter fuperates in velocity the flower ;
and to pronounce the Propolition in more proper terms ^ wc fay;
That if two Taps of unequal velocity, difcharge in equal times
equal quantities of Water, the greatneffe of the firil fliall be to
the greatneffe of the fecond, in reciprocal proportion, as the ve-
locity of thefecond to the velocity of the firft. As for ^xiimjrfe,
if the firfl: Tap fl^all be ten times fwifc.r than the fecond Tap, tt
will be neceffary, that the fecond be ten times bigger and larger
than the firft j and in fuch cafe the Taps fliall difcharge equall
quantities of water in equal times ^ and this is the principal and
moft important point, which ought to be kept alwaycs in minde,
for that on it well underftood depend many things profitable,
and worthy of our knowledge.

Now applying all that hath been faid neerer to our purpofe, I
confider, that it being moft true, that in divers parts of the fame
River or Current of running water,there doth always paffe equal
quantity of Water in equal time (which thing is alfo demon-
ftrated in our firft Propofition) and it being alfo true, that in di-
vers parts the fame River may have various and different veloci-
ty j it follows of neceffary confequence, that where the River
hath leffe velocity^ it fliall be of greater meafure, and in thofe
vparts, in which it hath greater velocity, it fliall be of leffe niea-
fure h and in fum, the velocity of feveral parts of the faid River,
fliall have eternally reciprocal! and like proportion with
their meafures. This principle and fundamental well eftablifli-
ed, that the fame Current of Water changeth meafiire, accor^
ding to its varying of velocity •, that is, Icffening the meafure,
V^hen the velcicity encreafeth, and encreafing the meafure, vVhen
the velocity decreafeth I paffe ta the cdnfidcratidn of many

par.

Of the Mensk RAT IOS Lih.i.

particular accidents in this admirable matter, and all depending
on this folc Propofition, the fenfe of which 1 have oft cepeated,
that it might be well underftood.

COKOLLAKIE L

A Nd firft, we hence conclude, that the fame Streams of a
^Torrent, namely, thofe ftreams which carry equal quantity of
Water in equal times, make not the fame depths or meafures m
the River, inwhich they enter, unlefTe when in the entrance in-
to the River they acquire j or to fay better, keep the fame velo-
city •, becaufe if the velocicities acquired in the River (hall be
different, alfo the meafures fliall be diverfe ^ and confequently
the depths, as is demonftrated.

COKOLLAKIE Ih

A Nil becaufe fucceflively, as the River is more and more full,
it is conftituted ordinarily in greater & greater velocity thence
it is that the fame ftreams of the Torrent, that enter into the Ri-
ver, make Icffe and leffe depths, as the River grows more and
more full j fince that alfo the Waters of the Torrent being en-
tered into the River, go acquiring greater and greater velocities,
and therefore diminifti in meafurc and height.

COKOLLAKIE III

TT7 E obferve alfo, that while the main River is (hallow, if there
fall but a gentle rain,it fuddcnly much increafeth and rifeths
but when the River is already fwelled, though there fall again a-
nother new violent (hower, yet it increafeth not at the fame rate
asWfore, proportionably to the rain which fell: which thing
we may affirm particularly to depend on this, that in the firft
cafe, while the River is low, it is found alfo very flow, and there-
fore the little water which entereth into ir^palTeth and runs with
little velocity, and confequently occupieth a great meafure :
But when the River is once augmented, by new water being alfo
made more fwift, it caufeththe great Flood of water which fal-
leth, to bear a lelTe meafure, and not to make fuch a depth.

COKOLLAKIE IV.

pRom the things dcmonftrated is manifeft alfo, that whilft a

. Tortent entereth into a River, at the time of Ebbe? then the

Torrent ru^veth with fuch a certain velocity, what ever i^J^^'

pa(nng

th-
all

foi

rei

ab
po
tk

CI
vo

AO. I.

Of RuKNtNG Waters.

pafllng by its cxtreamcft parts, wJiecewith it communicateth with
the River 5 in which parts, the Torrent Being meafured, ftall
l^aye inch a certain ineafure : bufe the RiverXwelling and, rifing,
arffo thofc parts of the Torrent augment in greatneffe and mea-

fbre the nfing, tlie ^;h^^^^ the rifing, which mouths

difchlrge c^'i'ial quanfme^^ water|m equal H therefpte the
velocity, by tlie lelTer mouth,flialf be^g^ tkan tlic velodity by,
the greater liiouth , and thus the Torrent fFiair/be retardccl From

ifeord

mar^

courft.

16*Rom wliich operation of NaWre proce^dejtli another effefi^
Worthy of coniiderationj and it is^tnat the courfe oif ^1|<; ^atCC
retarding, as hath been {aid in thofe ultimate parts of the t'orX
rent, if it fliall happen that the Torrent grow torbid andmud-^
dy, ind its ftreame be retarded in fueh a degree, that it is not

clear away

abietocirry away thoft minute grains of Earth, vyhich com«
pole the muddineiTe i in this cafe the Torrent fhall clear away
the mud, and carry away the Sana at the bottome of its own

Chanel, in the extream parts of its mouth, which raifed and
voided Sand, fliall again afterwards be carried away, vyhen the
River abating? tHe Torrent fliall return to mov^ withies .pjCfpiitiVe
velocity.

COkOLLAti,l^ VI.

WHilft it IS demonfirated , that the fame water hath different
meafiircs in its Cliariel or coiiife, according as it varieth in
velocity jfo that the irieafure of the water is alwayes greater,wHere
the velocity is lefTer ^ and on the contrary, the meafure leifferj
where the velocity is greater : from hence we may moft ele-^
gantly render the reafbn of the ufual Proverb, Tah^ heed of the
fiiU waters : For that if we confider the felf fame water of a
River in thofe parts, wherein it is Icfs fwift, and tiience called fiiU
OY fmooth vvater , it fliall be, of necefllty , df greater meafure
than in thofe parts, in vvhich it is more fwift, ^nd thcrefpre or^i-
tiafily SMl be alfo more deep and dangerous for paflengersj
whence it is well faid, take heed of the fiill IVaters j and this
faying hath been fince applied to thmgs moral

CO-

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Of the Mensuration.

Lih.v

-COKOLLAKIE VII.

¥ Ik^wife, from the things dcmonftrated. may be concluded,
that the windesj which flop a Kiver^arsd blowing againft the
Current, retard its courfe and ordinary velocity fliall neceflarily
ampUfiethe meafure of the fame River, arid confequently (hall
be, in j^reat part, caiifcs i or we may (ay, potent con-caufes of
making the extraordinary inundations which Rivers ufe to make.
And its^ nioft certain, that as often as a ftrong and continual wind
fliaJlbl,bw againft the Current of a River, and (hall reduce the
Watc^r of the River to fuch tardity of motion, that in the time
wherein before it run five miles, it now moveth but one, fuch a
River will increafe to five times the meafure, though there fliould
not be added any other quantity of water j which thing indeed
hath in it fomething of ftrangej but it is moft certain, for that
look what proportion thewaicer? velocity before the winde, hath
to thj^ V^ocity after the wii.cit, and fueh reciprocally is the mea-
fyrfc'of;thcf fame water after the winde, to the meafure before
the w^ride \ and becaufe it hath been iuppofed in our cafe that the
vdbdty is diminiflied to a fifth part, therefore the meafure fliaH
btiincttafed five tihies more than that, which it was before.

C OKOLLAKIE VIII.

^rtrtX bave^alfo probable the caufc of the inundations of Tybcr^
" -^{jjch befel at Konte^m the time of Alexander the Sixth,& of
Clement the Seventh 3 which innundations came in a ferene time,
and without great thaws of the Snows s which therefore much
puzzled the wits of thofe times. But we may with much pro-
bability affirm, That the River rofe to fuch a height and excref-
ecniei. by the retardation of the Waters dependant on the
boiflirous and con/i^nt Winds, that blew in thofe times, as is no-
ted in the memorials.

C OKOLh AIilt. IX-

TT being moft manifeft, that by the great abundance bf Water
the Torrents may increafe,and of themfe Ives alone exorbitantly
fwell the River h and having demonftrated that alfo without new
Water^ but onely by the notable retardment the River riifeth and
increafeth in meafure, in proportion as the velocity decreafeth :
hence itis apparei^t, that each of thcfe caufes being able of it felf,
and feparate from the other to fwell the River ; when it ftall
happen th;it both thcfe two caufes confpire the augmentation^^*

tih.r: OfRviiiYiiU'G WAtEks;

the Riverain fuch a cafe there muft follow very great and irrt*
pable inuundatibnS.

VOROL L AKIE X

ID K6m what hath bech demdnftrated, we may with facility rc-
folve the doubt which hath troubled^and ftill pofeth the moft
diligent , but incautelous obfervcrs of Rivers , who mcafuring
the Streams and Torrents which fall into another River j as thofc
forinftanccjWhich enter into the Po^ot thole which fall into ft*
btt \ and having fumiVicd the total of the le mealures, and con-
ferriiig the meafures of the Rivers and Brooks, which fall iuto
Titer, with the meafure of Tiber ^ and the meafures of thole which
difirtibogue into Pc^jWith the meafure i oy they find them not
equal, as,it feems to them,they ought to be, and this is becaule
they have not well noted the moft important point oi the varia-
tion of velocity, and how that it i^ the moll: patent caiifc bf won-
derfully altering the meafures of running Waters 5 but wemoH:
facilly refolving the doubt, may fay that thefe Waters dirtiinifli
the meafure, being once entered the principal Channel , Becaufe
they incfcafe in velocity.

COKOLL AKIE XL

TTHrough the ignorance of the force of the velocity of the Wa-
ter,in altering its mcafure,& auginenting it when the velocity
diminiflieth ; and diminifliingit when the velocity augmentcthj
The Architeft Gioi^dnni Font an a, endeavoured to meafure^ and
and to caufe to be nleafured by his Nephew, all the Brooks and
Rivers which difcharged their Waters intoTiher , at the time of
the irinundation^ which happened at Rome in the year ip8,
itid pabliOied almall Treatife thereof, wherein he iummeth up
the mclfitres of the extraordinary Water which fell mto Tijer,
and made account that it was about five hundred ElU more than
ordinary and in the end of that Treatife concludeth, that to re-
move the Innundatioii wholly from Rome, it would be necefTary
to make two other Channels, equal to that it prefent, and that
kffe would not fuffice •, and finding afterwards that the whole
Stream pafTed under the Bridge Qnattro^Capi, (the Arch where-
of is of a far lefs nieafute then five hu.idred Ells^ concludeth,
that under the laid Bridge paft a hundred fifty one Ells ot Water
COttiprelTcd, (1 have fet down the precife term of comprcit Wa-
t€r, written by Font ana) wherein I finde many errors.

thefirftofwhichis to think that the meafures ot thefe Wa-
t^f^contrfedinthe Channels of thofe Brooks and m^^s,

Cccc ihoula

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Of the M E N S U R A T I p n i-^^-

ftould mabtaui themfelv.es the f^me in Tiber ^ which by his leave,
is moft falie, when ever thofe waters reduced into T/i^r , retain
not the fame velocity which they had in the place in which F en-
tana and his Nephew meafured them : And all this is manifeft
from the things which we have above explained , for, if the Wa-
fers reduced into Tiiirr increafe in velocity, they decreafe in mea-
for<: r .%i4 '^j\^y.^m!^9^kM Y^^^^^ ^^^^

- Secondly, Iconfider that the ineafures of thofe Brooks and
Kivers , which enter into Tiber at the time pf Innundation , arc
jiot between themfelves really the f;ame, when their velpfities are
not equal though they have the fame names of Ells and Feet ^
for that ICS ppflible that a difinbpguement of ten Ells requadratcd
(to fpeak in the phr^ife of Fontand) of one of thofe Brooks,
jpoight difcharge into Tiber at the time of Innundation, four, ten,
A^id twenty times lefj Water, than another mouth equal to the
liiift in greatneft, as would occur when the firfi mouth were four,
^i^p, or twenty times lefsfwift than the fecond. Whereupon^
.wiLilftiF<?/«M«4 fummesuptheElls and Feet of the meafuresc^
thofe Brooks and Rivers into a total aggregate , he commits the
lame error with him, which would add into one furome diverfc
moneys of diverfe values , and diverfe places, but that had the
fame name ^ as if one fliould fay tenCrowne of money,
four Crowns of Gold, thirteen Crowns of Florence^ five Grown^
%^i}^^nic$^ and eight Crowns of Mantua^ ftould make the fame
(\|^me wit;b forty Crowns of Gold, or forty Crowns of Mantna'
: I Thi^4iyi might happen that fome River or Current in the
l^^rts nearer Komy in the time of its flowing , did not fend forth
iipf^qre Wa,fer than ordinary j and however, its a thing very clear,
liat vvhijft the ftream came from the fupcrior parts, that fame
^k09k or River would be augmented in meafure , as hath been
.i\pt€;4 fourth CmZ/^r)' i in fuch fort, ihat Fontanarmght
ii^ve inwkated, apd noted that fame River or Current as con-
Cttfi-ing to the Innundation, although it were therein altogether
ypcpncerned.

,v Jylpreoye^^^ in the fourth place wemuft note, That it might
fq fell out, that fuch a River not onely was unintereffed in the
^n^und^|tion, though augmented in meafure, but it might I fay
happen, that it was inftrumental to the affwaging the Innunda*-
tion, by augmenting in the meafure of its own Channel j which
flatter is fufficiently evident , for if it be fuppofed 'that the Ri-
ver ia the time oftlood, had not had of it felf, andfron\ its pro*
per fprings n>pre Water than ordinary, its a thing certain, that
the Wan^rpfTiierrifing and increafing j alfo that River, to k-
v-i felf wViUthc^ Water otTiber, would have retained fome of

Lfb:t. Of Kui^Hif^o Wxttts.

its Waters ill its own Chanel, without difcharging them into Ty-
Ber, or elfc would have ingorgcd and iwallowed (if 1 may fo fay)
fome of the water of Tyber y and iri this cafe, zt the time of in-
Uhdation, lefTe abundance of water would have come to Rom^^
and yet nevertheldfe the meafure of that River would have been
increafed.

fifthly, f a/7//i///ideceiveth himfelti when he concludeth, that
fo rcmovc'the Inundation from Rome, it would be neceffary to
make two other Chancls of Rivers, that were as large as that,
which is the prcfcnt one, and that lefs would not fuffice, which,
1 fay, is a fallacy : and to convince him calily of his errour, it
fufficeth to fay, that all the Streams being paifcd under the Bridge
QyjttrO'C^ph he himielf attclls, a Channel would fuffice on-
ly of the capacity of the faid Bridge, provided that the Water
there might run with the fame velocity, as it did under the Bridge
at the time of Inundation ^ and on the contrary, twenty Cur-
rents of capacity equal to the prefent one^ would not fuftbe, if
the water rtiould run with twenty ticrte^ lefs velocity, than ic made
at the time of the Inundation.

Sixthly to meit feemethagreat weaknefTe to fay, that there
fliould paffe under the Bridge Qnattro^Capi, an hundred fifty One
dls of water compreffedi for that I do not undcrftind thacWi-
tttis like Cotton or Wool, vvhich matters may be preft and trod^
asithappcncth alfo to the air, which receiveth compreffion in
fuchfort, that aftet that in fome certain place a quantity of air
(hill be reduced to its natural conftitution y and having taken up
alf the faid place, yet ncvertheleffe compreffing the firft Ait
with forc^ and violence, it is reduced into far Icf^ room, and will
admit fdiii' or fix times as much air, as before, as is cxperinieit^
tally * (een in the Wind-Gun, invented in our dayes by MrKm^
cchio Vincent) of Vrbin, which ^to^QVty of the Air of admit-
finTCondenfatidn, is alfo feen in the portable Fountains of the
ftme Af. Vtncen%o : Which Fountains fpirt the Water cfn high,
by force of the Air compreffed, which whilft it fecks to redudc
its felf to its natural conftitution, in the dilation caufeth that vi-
olence. But the water can never, for any thing I knov^, crowd,
or prefs fo, as that if before the compreffion it held or po(feft a
place, being in its natural conftitution, I believe not, I fay, that it
is pofllblc, by preffing and crowding to make it poffefs lefs room,
fo-r if it Were poffiblc to comprcfs the Water, and make it to oc-
cupy a lefs place, it would thence follow, that two VclTcls of
dtjal meafur^i but of unequal height, fliould be of unequal cap:!,
city, and that fliould hold more water which was higher j alfb i
Cylinder, or other Veffel more high than broad, would containd
tndre water etcaed, than being liid along i for that being cre^

Cccc 2 ta.

* Arid as is at
Iirge dcmonftrated
by that moft excel-
lent and Honour-
able pcrfonage iVir»
Bailff in the indu-
firious experiment
of his Pneumatic

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

Vf the l^EUs UK KT ion Lib.v

, the water put therein would be more prefied and crowded.

And therefore, in our cafe, according to our principles wc will
fay, that the water of that Stream pafseth all under the faid
Bridge QudttrO'Cafh for that being there moft fwift, it ought of
confequeuce to be lefs in meafure.

And here one may fee, into how many errours a man may run
through ignorance of a true and real Principle, which once known
and well underftood, takes away all mifts of doubting) and ea-
fily rcfolveth all difficulties.

C 0 KOLhAKlE. XIL

nTHrbugh the fame inadvertency of mt regarding the variation
of velocity in the fame Current,there are committed by Ingi-
neers and Learned men, errours df very great moment (and I
could thereof produce examples, but for good reafons I pafs
then^pver in filence) when they think, and propofe, by deriving
new Channels from great Rivers, to diminilh the meafure of ihe
water in the River, and to diminilh it proportionally, according
to the meafure of the Water which they make to pafs through
the Channel, as making v.g. a Channel fifty foot broad, in which
the derived water is to run waft, ten foot deep, they think they
have diminiflied the meafure l>f the Wat^r in the River five hun-
dred feet, which thing doth not indeed fo fall out ^ and the rea-
fon is plain ^ for that the Ch.anel being derived, the reft of the
biain River, dimf niftieth in velopity, and therefore retains a grea-
ter meafure than it had at firft before the derivation of the Cha-
nel ; and moreover, if the Chanel being derived, it (hall not
confcrve the fame velocity which it had at firft in the main Ri-
ver, but fliall diminifh it, it will be neceffary, that it hath a grea-
ter meafure than it had before in the River j and therefore
to accompt aright, there jliall not be fo much watqr derived into
ihe Channel, as fhall diminifh the River, according to the quanti-
ty ojf^jhe water in the Chantjel, as is pretended.

C OKOLhAKlE XUI^

TTHis fame confideratidn giveth me occallon to difcover a moft
; ordinary errour, obferved by me in the bufineffe of the wa-
ter of Ferara , when I was in thofe parts , in fervicc of the moft
kevercnd and Uluftrious Monfignor Corfwi', the fublime wit of
whom hath been a very great help to me in thefc contemplarionsj
its very true , I have been much perplexed , whether I (hould
commit this particular to paper , or paffeit over in filence, fo*^
that i have ever doubted , that the opinion fo common and
? more-

Likil 0/ Running Wateks.^

moreover confirmed with a mbft manifeft experiment , may not
onely iifiakv this my cbnjefiUre to be efteemed far from true,
but alfo to dlfcredit with the World the reft of this my Treatife:;
Nevcrtheleffe I have at laft refolved not to be wanting to my
felf • and to truth in a matterof it felf , and for other confe*^
quences moft important j nor doth it fceth to me requifite ia
difficult matters , fuch as thefe we have in hand , totefjgne oiir
felvestb the common opinion, fince it would be very ftrangeif
the multitude in fuch matters fliou Id hit 6n the truth, nOr ought
that tb' be held diffitult^ in which even the vulgar do- know the
truth and right j bclldes that I hope more ver to prove all in fueb
fbrt , that perfons of folid judgment , fliall teft fully perfwadcd^
fo that they but keep in mind the principal ground and fbundation
of all this Treatife jand though that which I vi^ill propoife,bei par-
ticular.as Ihave faid, pertaining onely to the interefts of Ferara':,
yet nevcrthcIejQTe from this particular Doftrine well underftobd^
good judgement may be made of other the like cafes in general;

Ifay then, for greater jperfpecuity, and better piTderftandkig
of the whole, That about thirteen miles above ferara^ near to
SteUata:^xhc maiitH^f Fo, branching it felf into two parts, with bne
ofits Armsitcbmeth clofe tof ^Mr^, rietaining the name of t hp
fo of Ferara j and here again it divideth it felf into ewo othe|
branches, and that which continuethon the right hand, is called
ihcVo of Argentdj 2nd of Vrivtaro j and that on the left the
df Volaha. Bua for that the bed of the P^'bf Ftrard being here-
tofore augmented and raifed, it foUoweth thatit refteth wholly
deprived of the Water of the great Pa, except in the time of it9
greater fwelling i for in that cafe, this Vc Ferara htin^ rd*
ftrained with a Bank near to Bondeno, would come alfo in the
oveiflavvingsof the main Po^ toM>efree fromits Waters 'But the
Lor^s<)f Ferara 2tth viront at fuch time as the P<? threateneth zo
Sreak but , to ciit the bank j by which cutting, there ilif-
gorgethfucha Torrent of Water, that it is obferved, that the
ttiain Pi> in the fpace of fome few hours abateth near a foot? and
all perfons that 1 have fpoken with hitherto, inoved by this cH-
perimcnt, think that it is of great profit and benefit tokeq) ready
this Vent, and to make ufe of it in the time of its fuUneffe. And
iiid^d, the thing confidered fimply, and at the firft appearance,
it feetneth that none can think otherwife^ the rather- for that
iitany cxaminina the matter narrbwly , nieafure that body of
Water which runneth by the Channd^ or Bed of the ¥d of Fera-
ra, and make account, that the body of the Water of the great
P(?, is diminiihed the quantity of the body of the Water which
runneth by the ?o of Ferara. But if we well remember what
hath been faid in the beginning of the Tf eatife, and htiw mu^h

> Ofibe M E N S U R A. T I o i«. L^- h

the variety of the velocities of the laid Water uuporteth, and the
knowledge of them is neceffary to conclude the true quantity or
the runriine Water , we (hall tiude it manifeft, that the benetitoi
this Vent 13 far leffe than it is generally thought : And mcreovcr,
wefhall finde,ifl deceive not my felf, that there tolloW trom
thence io many mifchiefs, that I could greatly incline to believe,
that it were more to the pui pole wholly to ftop it up, than to
maintain it open: yet lam not fo wedded to my opinion, but
tbat I am ready to change my judgement upon ftrength of better
reafonsiefpeaally ofone that (hall have firft well undetftood
thebcginning ofthis my dilcourXb, which I Irequently inculcate,
becau^ its ^bfolutely impoflible without this advertifefflent tO,
ttsat . of theic matters, and n9t commit very great ctrours.
• i proppfe therefore 50 confideration, that although it be true,
that whilfttKe water of the main is at its greateft Ji^iaht, the
Bankand.Pain thencutof the f e of Ftrara, and the iuperior
waters having a very great fall into the Channel of t'erara , they
precipic9te into the fame with great violence ar.d velocity , and
with the fame in the beginning, or little leffe, they run towar^*
the Fo oiVolana, and of Argema on the fca coafts ; yet after the
foftcc of fome few hours, the Fo oSFerara being full, and the fu-:
perior Waters not finding fo great a diclivity there, as they had
at the beginning of the cutting, they fall not into the fame With
the former velocity, but with far leffe, and thereby a great deal
l«ilc Water begins to iffue from the great Fo y and if we dih-
gently compare the velocity at the firft cutting, with the velocity
oftne Water after the cutting made, and when the Fo of Ferara
(hall be full of Water, we fliall finde perhaps that to be fifteen of
twenty times greater than this , and confequently the Water
which iffues from the great fo,that firft impetuofity being paft»
ftall beonely the fifteenth or twentieth part of that which iuued
4tthe beginning i and therefore the Waters of the main f 6 Wl||
return in a fmall time almoft to the firft height. And here I wul
pray thofe who reft not wholly fatisfied with what hatli been faid,
that for the love of truth, and the common good , they would
pleafe to make diligent obfcrvation whether in thctimeofffeat
Floods,thefaidBankorDamatBo»f/«;«ois cut , and that in few
hours tile main diminifticth,as hath been faid about a foot Itt
its heighr; that they would.obferve I fay, whether, a day or twa
ieine paft,the Waters of the main Fo return almoft to their firtt
height i for if this fliould follow, it would be very clear, that the
benefit Which refulteth from this diverfion or Vent, is not fo gre«
»8 is univerfally prefumed i I fay, it is not fo great
freCumed ^ becaufe , though it be granted for true , «»*
Ihe Waters of the main Fo , abate at the bepaaiofi f*

Lih.i^ 0/ Running WAT%iisJ V7

the Vent, yet this benefit happens to be but temporary and for i
few hours : If the rifing of Po^ and the dangers of breaking forth
were of (hort duration, as it ordinarily bcfalleth in the overflow-
ings of T^rfeiitSjinftich a cafe the profit of the^Vent would (fe
of ibmb efteem : But bccaufe the fweHings of f <? continue fik
thifcy, or Sometimes for forty dayes, therefofe the gaih which
mTults frbm f!he Vent ptX)Teth to b^/ irtC(>kifiderabile. It rertiain-
cth'nc^ to erihfidcr jthe^fiotable harms which follow the faiU
Sluice or Vent^ tbit f6 rtfldai<>n bcsing i^^ the pr6fit and

the detriment compared, one may -rightly judge, and chbdfe chat
which (hall be moft convenient. The firft prejudice therefor^
whicharifcth fromthisV^nt or Sluice, is , ThSft the Channels oif
¥itara-i?nvi\ifi)'^2iVi6.Volana filling with W^a-ter, all th0fc^aff«
fxom Bondertot^ the Sea fide a^e ^Harmed and endangered
thereby. Secondly, The Waters of the ?o oi Yrimxto having
fr^e ingreffc into the upper Valleys, tihey fill them to the great
damage of the Fields adjacent, and obftruft the coarfe of the
ordinary Trenches in the fame Valleys j infomuch that all tfcNi
care, coft, ai^ labour about the di^aifting^ and freeing the ^upper
Valleys ffcntt Water, Wbuld alfo betome vain arid ittcffeiftualj
Thirdly, I confider that tbefe Watisi^s of the Pa of Fir^r^ being
paffed downwards towards the S^a, at the time that the ftlain P»
was in its grefttet eitcrefc^rt^es and teights, it Is mknifeft by ejcpe-i
tience, that when the great ?o dinfMniflietb, then thefe Wat^fl
faffed by the Pi? of fetata begin to retatdiii their courfe, and
finally come to turn the current upwards towards Ste//4M,refting
firft iu the imermediate tiine, almoft fixed and ftanding , and
therefore dcpofing the muddincffe, they fill up the Channel of
the River or Current of ^erara. Fourthly and laftly, There
foUoweth from this fame diverfion another notable damage , and
ft is like to that which followeth the breaches made by Rivers j
near to which breaches in the lower parts, namely below the
breach, there is begot in the Channel of the River, a certain ridge
Of fliclf, that is, the bottom of the River is raffed, as is fuflSlciently
flianifeft by experience^ and thus juft in the fame manner cutting
the Bank at Bondeno^thtit is at it were a breach made,from which

followeth the rifing in the lower parti of the main ?o, being paft
the mouth of ?amaro'^ which thing,how |)ernitioas it is,Iet any one
judge that underftandeth thefe matters. And therefore both for
the fmall benefit, and fo many harms that einfne from maintaiit-
ing this diverfion, I fliould think it were more found advice to
keep that Bank alwaie^whdlc at Bandeftff, or m any other conve-
nient place, and not to permit that the Water of the Grand ?ff

fliould ever come near to Ferdt^:

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

Of the Mensuration

COKOL L AKiE XIV.

IN the Grand Rivers, which fall into the Sea, as heie in Italy
Poi Adige^" and yir//(?,which are armed with Banks againft their
excrefcencies, its obferved that far from the Sea, they need
Banks of a notable height , which height goeth afterwards by
dcgreesdiminiftiing j themore it approachetb to the Sea-coafts:
in fuch fort, that the ?o, diftant from the Sea about fifty or fixty
miles, at Fertfr4 , (hall have Banks that be above twenty feet
higher than the ordinary Water marks j but ten or twelve milcs
f.om the Sea, the Banks are not twelve feet higher than the faid
ordinary Water-marks, though the breadth of the River be the
fame, fo that the excrefcence of the fame Innundatioh happens
to be far greater ia meafure remote from the Sea, then near j and
yet it fliould feeni, that the fame quantity of Water pafling by
every place, the Ri ver (hould need to have the fame altitude of
Banks in all places : But we by. our Principles and fundamentals
may be able to render the reafon of that efFeft , and fay i That
that exccffe of quantity of Water, above the ordinary Water,
goeth alwaies acquiring greater velocity i the nearer it approach-
etb the Sea,and therefore deereafeth in meafure, and confcqucmy
in height-And this perhaps might have been the caufc in great
part, why the Tyber in the Innundation Jnno 1 578. iffucd not
forth of its Channel below Rome towards the Sea.

COKOLLAKIE XV.

FRom the fame Doftrine may be rendred a moft manifeft rea-
fon why the falling Waters golefTening in their defcent , fo
/ that the lame falling Water , mcafured at the beginning of
iti.f^ll, is greater, and bigger, and afterwards by degrees leffenetb
in meafure the more it is remote from the beginning of the falU
Which dependeth on no other, than on the acquifitlton, which
it fucceflively makes of greater velocity j it being a moft fami*
liiir CO siclufion among Philofophers , that grave bodies falling,
the more they remove from the beginning of their motion, the
more they acquire of fwiftnelfe \ and therefore the Water, as a
grave; body , falling, gradually velocitates , and therefore de»
creafeth in meafure, and leffencth.

COKOLLAKIE XVI.

A Nd outhe contrary ^ the fpirtings of a Fountain of W^^^**'
^ A which fprVng on high , work a contrary efFca f^^^^jV

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

Lib.i. 0/ Running VVatirs.

in the beginning they are fmall , and afterwards become greater
and bigge j ind ihe reafon is moft manifeft , becaufe in the be-
ginning they are very fwift > and afterwards gradually relent
their impetuofity , and motion , fo that in the beginning of the
exeurfion that they make , they ought to be fmall , and after-
wards to grow bigger , as in the tffcfk is feen.

APPENDIX. I.

yNto the errour 6f not confidering how much the different
I velocities of the fame running water in feveral places of
its current , are able to change the mcafiirc of the fame
Water, and to make it greater, brleffe, I think , if I be not
deceived , that Ginlio Fronttno a noble antient Writer, may
have fain in the Second Book which he writ , of the Aquedufts
of the City of Rome : Whilft finding the meafure of the Water
Xommerttatiis leffe than it was in erogattone 1 263. QninarieSy he
thought thit fo much difference might proceed from the negligence
of the Meafures ; and when afterwards with his own ijiduftry he
meafured the fame watet at the beginnings of the Aquedufts,
finding it neer 10000. QHinarUrh'iggct than it was inCBmmenta-
tin he judged , that the overplus wis imbeziled by Minifters and
Partakers i which in part might be fo , for it is but too true, that
the publique is almofl alwayes defraiided ^ yet neverthelelTe, I
verily believe withal j that befides the frauds of thefe Officers,
the velocities of the water in the place wherein Fromino meafii-
red , it might be different from thofe velbcities , Which are
found in other places before meafured by others ^ and there-
fore the meafures of the waters might , yea ought necffarily to
be different, it having been by us demdnftrated , that the mea-
fures of the fame running water have reciprocal proportion to
their velocities. Which Frontirio not well cdnfidering, and find-
ing the water in Coirimcntariis t2 75$. Qjinaries in etogati-
one 14018, and in his own meafure ad capita duBuum ^ at the
head of the fountain 42755- Qninaries ^ or thereabouts. He
thought, that in all thefe places there paft different quantities of
Water j namely, greater at the fountain head then that which Was
in Erogatiorie , atid this he judged greater than that which m$
in Comnientariit*

APPENDIX II.

Like miftake chanced lately in the Aqucdud of Acqna-
ifapla^ which Water fliould be 2600 Inches, and fo ihany
effeftively biigbt to be allowed j and it hath \ftttk ^iveri in
Dddd H

* CmmentariHt
bearcch many fcn-
fes , buc in chis
place Hgnigech a
certain Regifter of
the quiinticies of
the Waters in she
fv'veralpublique A-
quidudtof Rome;
which word I find
frequently ufed in
the Law-bpoks oi
antient Civilians :
And by errogation
we are to under*
i^and the diftribu-
cion or delivering
ouc of thofc ftorcf
of Water.

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

Of the M E N s u R A T I G ia; J-i^' i-

fd to be by the Signers of Bracciano to the Apojlolkk-Chamhen
andtherewasameafure thereof made at the beginning ot the
Aquedua j ^A/h\ch meafure proved afterwards much leffe and
(hort,confidcred and taken in Rome, and thence followed dil-
contentsand great diforders , and all becaufe this property ot
Running-Waters, of increafing in meafure, where the velocity
decreafed^ and of diminifliing in meafure, where the velocity
augmented, was not lookt into.

APPENDIX HI.

ALike errour,in my )udgement, hath beeen committed by
all thofe learned men , which to prevent the diverfion ot
the Reno of Eologna into F.o by the Channels ,\ through
which itAt prefent runneth, judged, that the Keno being in i^s
greatet'.excrefcence about 2000. feet , and the P^ being near
1000. feet broad,.they judged , I fay, that, letting the Ke;;^ into
P(>, it would have railed the Water of Pa tvvo feet j from which
rife, jtJii?»?oncluded afterwards moft exorbitant diforde^, either
ofextr;j^dinary Inundations, otelfe of immenfeand intolera-
ble ^xpences to the people in raifing the Banks of f o ^nd Re^,
, and wi^h iuch like weakneffes^ often vainly difturbed the minds
of the perfons concerned : But aow from the things demonitrar
:ted,it;ismanif^ft,That thex^e^fure of the Keno in Kenoywoulfi
he dkflFwn^, from the meafure; of Keno in Pa i in cafe that the
velocity of the in Po , (hould differ from the velocity

of Rem in Re»a,as is more exaftly determined in the fourth Pro-
jpofitioft.;

APPENDIX IV.

^1^1 <^ l^fshkewife are thofe Ingeneers and Artifts deceived j
J^i[j that have affirmed, That letting the Reno into Pa , there
would be no rife at all in the Water of Pa : For the truth
isj That letting Keno into F^>,there would alwaies be a rifing 5 but

ifometimes greater, fometimes lefTe, as the Pa fliall have a fwifter
or flower Current ^ fo that if the Pa fliall be conftituted in a great
Velocity, the rife will be very fmall ^ and if the faid Pa fliall be
flow in its courfe, then the rife will be notable.

APPENDIX V.

Nd here it will not be bcfides the purpofe to advertife,That
the laieafures, partments, and diftributions of the W^^^ts
^f Fountains, (:aiuiot be made exaSly , unlefs ther^ be con-

fldercd

lib.

Of Running W a t e r $.

iSdered ,bcfides the meafure, the velocity alip of the Wateri
which particular not being thprowly obibrvcd , is the caufe of
continual mifcariagcs in fuch like attairs.

APPENDIX VI.

Ilke confideration ought to be had with the greater diligence,
• for that anerrour thcreiii is more prejudicial j 1 fay, QUght to
"'be had by thofe which part and divide Waters 3 for the
watering of fields, as is done in the Territories of Bnfda^ Ber-
gama, Crcma, ?avia, Lodigiano^ Cremona^ and other places, :
Forif they have not regad to the moft important point of the
variation of the velocity of the Water, but onely to the bare
Vulgar meafure, there wilialwaies very great diforders and pre-
judices enfue to the perfons concerned-

APPfeNDiX VII.

T feemeth that one may obferve, that whilft the V^ater run-
neth along a Channel, Current^.or Conduit, its velocity is
retarded, withheld, and impeded by its touching the Bank or
fide of the ft id Channel or Current 3 which, as immo veable^ not
following the motion of the Water, interrupteth its velocity ;
From which particular, being truey as I believe it to be moft
true, andfromourconfiderations, we have an occafion of dif-
covering a^yery nice miftake^into which thofe commonly fall
wTio divide the Waters of Fountains. Which divifion is wont
to be, by what I havefeen here in Komi:, performed two w^yesj
the firft of which is with the mcafures of like figures, as Cir-
cles or Squares, having cut through a Plate, of metal fpcral
Circles orSquares , oncof half an inch, another pf one inch,
another of two, of three, of four, ^Nc with which they after-
wards adjuft the Cocks to, difpence the Wafers, The^oth^
mannerof dividing the Waters of Fountains, is with reaanglc
paralellograms, of the fame height, but of different Bafes, in fuch
fort likewife, that one paralellogram be of half an inch, another
of one two, three, dNc- In which manner of meafuring an4
dividing the Water, it fliould fce;n that the Cocks being . pUced
in one and the fam- plain, equidiftant from the level, or fuperior
Jiiperficiesof thewaccrof the Well ; and the faid meafures be-
ing moft cxaftly made^ tb> VVatcr ought confeqiiently alio to
be equally divided, and pAited according to the proportidn ot
the meafures. , But if wc well confider every particular, we fliall
finde, that the Cocks, they fucceffively are greater, difcharge
alwaies more Water than the juft.rquantity, m compatifan

D d d d a tlHf

0/tl&(?MENSUR AT ION i-^^'^'

thelefferi that is, to fpeak more properly, The Water which
paffech through the greater Cock, hath alwaics a greater pro-
portion to that which paffeth through the leffer, than the greater
Cock hath to the lefl'er. All which 1 will declare by an exam-
ple.

Let there be fuppofed for more plainnefs two Squares j (the
fame may be underftood of Circles, and other like Figures) The
firft Square is, as we will fuppofe, quadruple to the other , and
thefe Squares are the mouths of two Cocks ^ one of four inches,
the other of one : Now its manifeft by what hath been faid, that
the Water which paffeth by the lefs Cock, findcth its velocity
impeded in the circumference of the Cock *, which impediment

is meafured by the faid circumfe- ^ ^

rencc. Now it is to be confider-

ed, that if we would have the W a- _ _

tcr which paffeth through the i
greater Cock , to be onely qua- | ^ |
druplc to that which paffeth "
through the leffe, in tqual fpaces of time, it would be neceffary,
that not onely the capacity and the meafure of the greater Cock
be quadruple to the leffer Cock, but that alfo the impediment be
quadrupled. Now in our cafe it is true^ That the belly and
mouth of the Cock is quadrupled,and yet the impediment is nOt
quadrupled, but is onely doubled j feeing that the circumference
of tKe greater Square, is onely double to the circumference of
the lelTer Squart ^for the greater circumference containeth eight
of thofe parts, of which the leffer containeth but four , as is mi*
nifeft by the defcribed Figure j and for that caufe there (hi\i
pafsby the greater Cock, above four times as much Water, h
fliall pafs by the leffer Cock.

The like crrour occurreth alfo in the other manner of meafu-
ring the Water of a Fountain, as may eafily be collefted frorn
what hath been faid and obferved above.

APPENDIX VIII.

T He fame contemplation difcovereth the errour of thdfe
Architcds, who being to ereft a Bridge of fundry Arcbe$
' • <»vcc a River, confider the ordinary breadth of the Ritrer 9
which being 'z/, g. fourty fathom, and the Bridge being to corifift
of four Arches, it fufficeth them, that the breadth of all the four
Arches taken together, be fourty fathom j not confidering th?t
tti the ordinary Channel of the River, the Water hath oxf^ij
^^^^"^P^diments which retard its velocity i namely, the toucWtf^
and gliding along the two fides or fhores of the River.- bilt

the

Lib I. 0/ R U N N I N G W A t E R S.^

ihe fame water in pafling under the Bridge, in our cafe meeteth
with eight of the tame impediments, bearing, and thrufting upoa
wo fides of each Arch (to omit the impediment of the bottom,
for that it is the fame in the River, and under the Bridge) from
which inadvertency fomctimes fallow very great diforders, as
quotidian praaice ftcws us-

Appendix ix.

ITisalfo worthy to confider the great and admirable benefit
that thofe fields receive , which are wont to drink, up the Rain-
water with difficulty, through the height of the water in the
principal Ditches ^ in which cafe the careful Husbandman cutteth
away the reeds and rulhes in the Dicches, through which the
waters pafs ; whereupon may be prefently feen, fo foon as the
reeds and ruftiesare cat, a notable Ebb in the level of the water
in the Ditches h infomuch that fometlmcs it i^ obferved, that the
water is abated after the faid cutting a third and more, of what it
was before the cutting. The which cfFea feemingly might de-
tend on this, That, before thofe weeds took up room w the
Ditch and for that caufe the water kept a higher level, and the
faid Plants being aftcrwatrds cut and removed^ the water came to
Abate, pofleffing the place that before was occupied by the
weeds: Which opinion , though prdbable, and at firft fight fa-
tisfaaory, is neverthelefs infuffieient to give the total reafon of
that notable abatement which hath been fpokcn of : But it is nc-
cefTary to have recourfe to cur confider ation of the velocity in
the courfe of the water, the chiefeft and true caufe of the vari-
atibn of the meafure of the fame Running- Water for, that
itiultitude. trf re^ds, Weeds, and plants difperfed through the cur-
tent of the Ditch, do chance notably to retard the courle ot the
watervand therefore the meafure of the Neater increafeth i and
thofe impedhnents removed, the faitte water gaineth velocity,
and therefore decreafeth in meafure , and confcqucntly in

And perhaps this point well underftood, miy be of great
profit to the fields adjacent to the Vontine Fens, and I doubt not
but if the River Ni»/tf , and the other principal Brooks of thofe
Territories Were kept well eleanfed from weeds , their waters
Would be at a lower level , and confequently the drains of the
fields would run into them more readily it being alwaycs to be
held for undoubted, that the meafure of the water betore the
deanfing, hath the fame proportion to the meafure after clean-
fing that the velocity after the deanfing hath to the velocity
bcSretheclcanfing: Andbecdiifc thofe Weeds being eleanfed

away,

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2°K.B. 9,163

Of M E N S U R A T I O N

a^ray, the courfeef the water nocably increlifcth, it is therefore
neceffary tlut the faid water abate ia meafure^ and become
lower.

APPENDIX. X.

WE having above obferved lome errors that are commit*
ted in diftributing the waters of Fountains, and thofc
that ferve to water fields i it feemech now fitjby way of
a clofe to this difcourfe, to advertife by what means thefe divi-
Cons may be made )uftly and without error. 1 therefore think
that one might two feveral waycs exquifitly divide the water of
Fountains ^ The firft would be by diligently examining, Firft,
how much water the whole Fountain difchargeth in a determi-
nate time, as for inftance : How many Barrels, or Tuns it carri-
eth inafet time, and in cafe you are afterwards to diftribute
the water, diftribute it at the rate of fomany Barrels or Tuns,in
chat lame time i and in this cafe the participants would have
their punfiualfhares : Nor could it ever happen to fend out mor^
watery than is reckoned to be in the principal Fountain j as befel
GiuUo Frontinoy ^nd as alfo it frequently happeneth in the Mo-
dern Aquedufis, to the publiek and private detriment..
•:uThe other way of dividing the fame waters of a Fountam , is
alfo fufficiently exaft and eaiie,and may be, by having one one-
ly fee for the Cock or Pipe, as fuppofe of an inch, or of half ai\
inch j and when the cafe requireth to difpence two, three 5 and
more inches, take fo many Cocks of the faid meafurc as do eva-
cuate the water, which is to be emitted , and if we are to m^kc
ufeonely of one greater Cock , we being to place one to diG
charge for example four inches j and having the former fole mea-
fure of an inch, we muft make a Cock that is bigger, its trac,than
the Cock of one inch ^ but not fimply in a quadruple propor-
tion, for that it would difcharge more than juft fo much water)
as hath been faid above i but we ought to examine diligently
how much water the little Cock emitteth in an hour *, and thco
enlarge 5 and contraft the greater Cock , fo, that it may dif-
charge four times as much water as the leffer in the fame time j
and by this meafis we (hall avoid the diforder hinted in the
feventh Appendix. It would be neceffary neverthelefs, to ac-
commodate the Cocks of the Ciftcrn io, that the level of the
water in the Ciftern may alwayes reft at one determinate mark
above the Cock , otherwife the Cocks will emit fotnetimes
greater , and fometimes lejSe abundance of water : AncJ becaufe
it may be that the fame water of the Fountain may be fometimes
more abundant, lometimes lefs i in fuch cafe it will be ncceffary

Liku (9/ Running VVatirI?

to adjuft the Ciftern fo, that the excefs above the ordinary wa^*
ter^ difcharge into the publick Fountains, that fo the particular
participants may have alwayes the fame abundance of
water. ' '

APPENDIX XL

MUch more difficult is the divifion of the waters which
ferve to water the fields, it not being poffible to obfervc
fo 'Commodioufly, what quantity of water the Whole
bitch fcndsforth in one dcrcrminace tirffe, as may be done in
Fountains : Yet neverthelcls, if the ftijcond jiropoiicion by us a
little bdow demonft rated i, be Well 'Crnderftood , there may be
thence taken a very fafe and ;uft waV to diftrlbute fuch waters.
The Propofition therefore by us demonftrated ig this : If there
be two Sefti6ns,{namely two mouths 6f Rivers j) the qaanrity of
the water which palTeth by the firft, ibaih a proportion i to* that
which palTcth by thefecond , compounded of tlie proportions of
the firtt Seftifon to the fecond; and of the velocity through
thefirft, to thc velocity through the ftcond : As I will dcdare
forexample byhelpof prafticc'that I may be uhderftobd -by
allvin a matter fo important. Let^uhe two mouths of the
Rivers be A, and B, and let
the mouth A be in intafure
and content thirty two feet,

and the mouth B, Cjght feet. ' mo*-' 'jr .- i >H'

Here youn 'tnuft take notice, . n^^-^v-. — 8 4?
that it is not alwayes true, that 1 B- 8. | ^ ' '

the Water which pafTeth by A,

hath the fame proportion to that which pafTethby B, that the
fiKmth A hath to the mouth B i, but onely when the velocityes
by each of thofe palfages are equal : But if the velocityes ihall
be unequal, it may be that the faid mouths may emit equal
quantity of Water in equal times, though their meafure be un-
equal J and it may be alio, that the bigger doth difcharge a great-
er quantity of Water : And laftly, it may be, that thelefs mouth
difchargeth more Water than the greater j and all this is mani-
fcft by the things noted in the beginning of this difcourfe, and
by the faid fecond Propofition. Now to examine the propor-
tion of the Water that pafTeth by one Ditch, to that which paf-
fcth by another , that this being known , the fame Waters and
mouths of Ditches may be then adjuftcd, we are to keep ac-
count not onely of the greatnefs of the mouths or paffages of the
Water, but of the velocity alfo which we will do, by firft find*
ing two nambers that have the fame proportion ihietWecri^ tJietil^

felves^'

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2°K.B. 9,163

Of the MENSURATlOii.
felves, as have the mouths , which are the numbers 3a

Lib. r

and 8

A. 32.

B. 8.

32. 8. 4.

in our example : Then this
being done , let the velocity
of the Water by the pafla-
gcs A and B, be examined
(which may be done keeping
account what fpace a piece
of Wood 5 or other body that

fwimmeth, is carried by the ftreaminone determinate time j as
for inftance in 50 pulfes) and then work by the golden Rule, as
the velpcicy by A, is tdltfie velocity by B, fo is the number 8, tO
another number, which is 4. It is clear by what is demonftra-
ted in the faid fecond Propofition, that the quantity of water,
which paffeth by the mouth A, (hall have the fame proportion of
that which paffeth by the mouth B, that 8 hath to i . Such pro-
portion being compofed of the proportions of 3 a to 8,and of 8 to
4^namcly,tothe greatncfs of the mouth A, to the greatnefs of the
mouth B,and of the velocity in A,to the velocity in B. This being
done , wcmuft then contraft the mouth which difchargeth more
then its )uft quantity of water,or enlarge the other which difchar-
geth kfs,as (hal be moft commodious in praftice, which to him that
hatli underftood thi$ Httlc that hath been delivered , will be very
afie.

APPENDIX XII.

THefe opperations about Water, as 1 have hitherto on fun-
dry occafions obferved, are involved in fo many difficul-
ties, and fuch a mukiplicity of moft extravagant accidents,
that it is no marvel if continually many, and very important er-
roursbe therein committed by many , and eyen by Ingenecrs
thcmfelves,and Learned-men h andbecaufe many times they
concern not onely the publique, but private interefts : Hence it
is, that it not onely bclongcth to Artifts to treat thereof, but very
oft even the vulgar themfelves pretend to give their )udgei^nt
therein*: And I have been troubled many times with a neceffity
oftieating, not onely with thofe, which either by praaice, or
particular ftuuy, underftood fomewhat in thefe matters ; but alio
with people wholly Toid of thofe notions, which are neceffary tor
one that would on good grounds dil'courfe about this particular^
and thus many times have met with more difficulty in the thick
skulls of men, than in precipitous Torrents, and vaft Fennes.
And in particular,I had occafion fome years paft to go fee the
Cave orEmiffary of the Lake of Perugia, made many years agon
by Braccio Fortobraccio^ but for that it was with great mines by
Time decay e(ij>ndrendred unufcful. it was repaired with in-

duftry

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2°K.B. 9,163

M^ih.il C/RuNNjNO Waters.

duftry truly heioicall and admirable, by Monfignor Uaffei Bai'-
berino, then Pretca tor the Vv ayes, and now Pope. And being
heccffitated, that I might be able to walk inthe Cave, and fot
other caulcs,! let doWn the SU'iccs of the laid Cave, at the mouth
of the Lake '; No fooner were they ftopt, but a great many of the
people of the Towns and Villages coafting upon the Lake
flocking thither, began to make grievous complaints,that if thofe
Shiices were kept (hut, not oncly the Lake would want its due
Vent, but alio the parts adjacent to the Lake would be over
flown td their very great detriment. And becaufe at firft appea-
rance their motion Teemed very realonable, I found my lelt hard
put to it, feeing no way to ptrfwaderuch a multitude , that 'che
prejudice which they pretended I (hould do them by keeping
the Sluices flwifor two dayes,was ablblutcly ii.feiilible '■, and that
by keeping them open, the Lake did not ebb iu the lame tune fo
much as the thicknelsofaflieet of Paper: And therefure 1 was
neceflitatedtomakeufe-of the authority 1 had, and lo followed
mvbufinefsas caufe required, without any regard to that Rab-
ble tumultuouny alTembled. Now when 1 am not workmg with
Mattock or Spade, but with the Pen and Difcourfe, I ™d to
demonftrate clearly to thofe that are capable of reafon.and that
have well underftoodthegroundof this my Treatife,^that the
fear was altogether vain which thofe people conceited. And
therefore I fay, that the Emiffary or Sluice of the Lake ot Pem-
ff/^,ftandinginthefamemannneras at piefent, and the water
pairing thovSw it with the fame velocity as now •, to examine
how much the Lake may abate in two days ipace we^ought to.-
conildcr, what proportion .the fuperficies of the whole Lake hath
to the meafure of the Sedion of the EmilTary, and afterwards to
infer that the velocity of the water by the Emiffary or Sluice,
lhall have the fame p.oport.on to the abatement of the Lake,
and to prove thorowly and clearly th.s difcourfe, I mtend to
demonftrate the following Propofition. . ^ • ^ ^
S^ppole a Veffel of any bigneffe, and that it hath an Emiffary
or Cock, by which it dtfchargeth its water. And look what pro-
portion ^he fuperficies of the
veffel hath to the meafure ot "K .-{^a "

theleaionofthecock,fuchptov \Z -" !-f „

portion fliall the velocity ot the -l^p -"k

Water in the Cock have to the c B t

abatement of the Lake. Let the

Veffel be A B C D, H 1 L B, through which the Water runneth,
the fuperficies of the Water in the Veffel A D, and the feaion
of the Cock H L : and let the Water. io .the Vdtel
be fuppofed to have falne in one determinate nme from A to K-
* E e e e '

0/ ^i&e M E N S U R A T 1 O N. Lib !•

I fay that the proportion of the fuperficics of the Veffel A D iS
in proportion to the meafure of the feSion of the EmilTaty
H L, as the velocity of the EmifTary or Cock to the line A F 5
which ismanifeft, for that the Water in the Vefsel moving by
the line A F i as far as F , and the whole mafs of Water A G
difcharging it felf, and in the fame time the fame quantity of
Water being difcharged by the fedion of the Emilfary H L i it
is neceffary by what 1 have demonftrated in the third Propofition,
andalfo explained in the beginning of this Treatife^ that the ve-
locity by the Emilfary or Cock be in proportion to thp velocity
of the abatement, as the fuperiicies of the Veffel to the mea-
fure of the feftion of the EmllTary, which was to be demon-
ftrated.

That which hath b en demonftrated in the VelTelj falls out ex-
^iftly alfo in our Lake of Ferngu^ and its Emifsary ; and becaufe
tlie immenfity of the fuperficiesof the Lake is in proportion to
the fuperficies of the Emifsary or Sluice, as many millions to
one, as may be eafily calculated j it is mianifeft, that fuch abate-
ment (hall be imperceptible, and almoft nothing, in two dayes
fpace, nay in four or fix : and all this will be true, when we
foppefe that for that time there entreth no other Water into the
Lake fromDitches or Rivolets, which falling into the Lake would
render fuck abatement yet lefs.

Now we fee, that it's necefsary to examine fuch abatements
and rififtgs, with excellent reafons, or at leaft, with accurate ex-
periments, bt:fore wc rcfolve and conclude any thing 5 and how
farre the vulgar are diftant from a right judgement in fuch
matters.

APPENDIX XIIL

I"^OR greater confirmation of all this which I have faid, I
^ will inftance in another like cafe, which alfo I met with here-
tofore, wherein, for that the bufinefs was not rightly un-
dcrftood, many diforders, vaft expences, and confiderable mif-
chiefs have followed. There was heretofore an Emifsary or
Sluice made to drain the Waters, which from Rains, Springs, and
Rivoletsfall into a Lake ^ to the end, the ftores adjoyning on
the Lake, (houldbefree from the overflowing of the Waters 5
but becaufe perhaps the enterprize was not well managed and
carried on, it fell out, that the Fields adjacent to the faid Chanel
cduld not drain, but continued under water h to which diforders
aptefent remedy hath been ufed, namely, in a time convenient
toftop^p the Sluice, bymeanesof certain Floodgates kept on
purpofefot^atend^ and thus abating the Level of the Water

lib.

Of R

U N N r N G

A T E R S.

in the Emiflary, in the fpace of three or four dayes , the Fields
have been haply drained. But on the other part, the proprietors
bordering on the Lake oppofed this, grievoufly coinplainirig,that
whilft the Floodgates are fliut, and the courfe of the Water of
the Sluice hindered, the Liike overflowes the Lands adjacent, by
meanes of the Rivers that fell into it, to their ver y great damage^
and lo continuing their fuits, they got more of vexation than fa-
tisfaftion. Now, being asked my opinion herein , I judged ic
requifite (fince the point in controverfie was about the riling
ind falling of the Lake) that the faid abatenient, when the
Floodgates are open, and increafe when they are {hut fliould be
exaftly meafured, and told them, that it might be cafily done at
k time when no extraordinary Waters fell into >he Lake, neither
of Rain, ot btherwife *, and the Lake v<^as undifturbcd by winds
that might drive the Water to any fide, by planting neer to aa
iflet, which is about the middle of the Lake, a thick poft', on
which fliould be made the marks of the Lakes rifing and falling
for two or three dayes. I vvbuld not, at that time, paWn, or re-
folutely declare, my judgment, in regard I might be , by divert
accidents miflcd. But this I told them, that (by what I have
demonftrated , and particularly that which I have faid above
touching the Lake" of Ferugiay I inclined greatly to think,
thatthefe rifings and fallings would prove imperceptible, and
inconfiderable and therefore, that in cafe experience fliouli
make good my reafon, it would' be to rib piirpofe fortHem to
continue difputing and wrangling, which cauieth,^
to the Proverb) A great deal of cry , but ^fpducetb not m

' Laftly, ic importing very much to know what a Kam contiL-
litied for many dayes can do iil r^ifin^ thciei Lakes, I will here in-
fert the Copy of a Letter, which t' vyfrit f^^ St^ttior
liUa GalzUh chief Phil ofopher tb tHe Grand! 5^
wherein 1 have delivered one of my toncieits ih this bujfceflfei and
it may be, by this L^tttt^lmzyi h^otk ^V(^^

Have faid above.

Of the M^^suK hx ion

Lib-v

The Copy of a Letter to S ignore Galileo
G A L I L /E I , Chief Tbilofopber to the moji Serene
Great Dn\e of IV SCANT.

Worthy and moji Excellent S i Rj

BN fatisfaftion of my promife, in my former Letters of
reprefcnting unto you fome of my Confiderations
made upon the Lake Tbrafimeno^ I fay. That in times
paft, being in Perugia^ where we held our General
Convention, having undcrftood that the Lake Thrafimeno , by
the great drought of many Moneths was much abated. It came
into my head, to go privately and fee this novelty, both for my
particular fatisfadion, as alio that might I be able to relate the
whole to my Patrons, upon the certitude of my own light of the
place. And fo beirg come to the Emiffary of the Lake, I found
that tke Level of the Lakes furface was ebbed about five Ro-
man FaJm^es of its wonted watermark, infomuch that it was lower
than the tranfome: of the mouth of theEmiffary, by the length
of : — — this defcribed line, and there-
fore Snio Wiiter iffucd out of the Lake, to the great prejudice of
all thk places and villages circumjacent, in regard that the Wa-
ter, wliich iifed to rtin from the faid Lake turned 22 Mills, which
BOt going 5 necefficated the inhabitants of thofc parts tO go a
dayes journey and more, to grinde upon the Tiber. Being retur-
ned to ffrji^i^, there followed a Rain, not very great, but con-
ftahiri arid even, which lafied for the fpace of eight hours, or
tfeercafeouts j and! it came into my thoughts to examine , being
iii Pefi4^4p^ how p^ch the Lake was increafed and railed by this
itkinj-T^^^^ that the Rain had
TSee^i univer^^ over all the Lakei and like to that vvhich fell in
FerH^^iJy'M tottfepurpofe 1 took a Glaffe formed like a Cy-
linder, about a palme high, and half a palme broad ^ and having
put in water fnfficient to cover the bottome of the Glaffe , I no-
ted diligently the mark of the height of the Water in the Glaffe,
and afterwards expofed it to the open weather , to receive the
Raine-water , which fell into it i and I let it ftand for the
fpace of an hour •, and having obferved that in that time the Wa-
ter was rifen in the Veffel the height of the following line ,

I confidered that if I had expofed to the fame rain fuch other vef-
fels et^ual to that, the Water would have rifen in them all accor-
ding to that meafure : And thereupon concluded, that alfo in all

the

Lib.u Of Runnikg Waters.

the whole extent of the Lake, it "was neccffary the Water fliould
be,raifcd in the Ipace of an hoar the fame meafure. Yet here I
confidered two difficulties that might diftucb and altar ftich an
crteft or at leaft render it inobferveable, which afterwards well
weighed, and refolved, left me (as I will tell you anon) in the
conclufion the more confirmed , that the Lake ought to be in-
creafedinthe fpace of eight hours , that the rain lalied eight
times that meafure. And whilft I again expofcd the Giafs to re-
peat the experiment, there came unto me an Ingeneer to talk
with me touching certain affairs of our Mon^jiiry of Vtrugi a, m A
difcourfing with him, I (hewed him the Glalo out ac my Cham-
ber-window, cxpofed in a Conrt-yard *, aud communicated to
him my fancy, relating unto biai all that 1 had done. But I
foon perceived that this brave fellow conceited me to be but of
a dull brain , for he fmiling faid unto me j Sir, you deceive
yourfelf: lam of opinion that the Lake will not be incrcaf-
ed by this rain , fo much as the thicknefL* of a* J^/io.
Hearing him pronounce this his opinion with ii ecnels and
confidence, 1 urged him to give me fome reafon for what he
faid, affuring him, that I would change my judgement , when I
faw the ftrength of his Arguments : To which he anfwered,that
he had been very converfant about the Lake, and was every day
upon it,and was well affured that it was not at all iiicreaied. And
importuning him further, that he would give mc fome reafon
for his fo thinking, he propofed to my confideration the great
drought pafTed, and that that fame rain was nothing for the
great parching : To which I anfwered, I believe Sir that the fur-
face of the Lake, on which the rain had fallen wasmoiftned, and
therefore faw noc how its drought , which was nothing at all,
could have drunk up any part of the rain. For all tnis he per-
fiftina in his conceit, without yielding in the leaft to my allega-
tion The granted in the end (I believe in civility to me) that
my reafon was plaufible and good, but that in pradile U could
not hold. Atlafttoclear up all, I made one be callfd, and
fent him to the mouth of the Emiffary of the Lake , with o.der
to bi ing me an exafi account, how he found the water of the
Lake, in refpca of the Tranfome of the Sluice. Now here,
SignoreG^W^^l would not have you think that 1 had brought
the matter in hand to concern me in my honour ; but believe me
(and there are witneffes of the fame ftiU living) that my mcffen-
aer returning in the evening to iemgia, he brought me veard,
that the water of the Lake began to run through the Cave 5 and
that it wa^ rifen almoft a fingers breadth above the Tranlomc :
Infomuch,that adding this meafure , to that of the lownefs of
*cfurfaceof the Lake, beneath the Tranfoafe betore the rain|^

* A Coya of Pope
f films ^arth fix
pence*

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2°K.B. 9,163

Of the Mensuration Lib. i

it was manifeft that the rifing cf the Lali<e caufed by the rain,was
to a hair thofe four fingers breadth that I had judged ittofce.
Twoda^es after 1 had another bout with the Ingencer , and re-
lated to him the whole bufincfs , to which he knew not vvhat to
anfwer.

Now the two difficulties which I thought of, able to impede
iiiy conclufion, were thele following : Firft, 1 con lidercd that
it might be, that the Wind blowing from the fide where the
Sluice ftood, to the Lake -ward ^ the mole and mafs of the Wa-
ter of the Lake might be driven to the contrary fliore jon which
the Water rifing, it might be fallen at the mouth of the EmilTa-
ry, and fo the obfervation might be much oblcured. But this
difficulty wholly vaniflied by reafon of the Aires great tranqui-
lity which it kept at that time, for no Wind was ftirring on any
fide, neither whilfl: it rained, nor afterwards.

The fecond difficuky which put the rifing in doubt, was,That
having obferved in F/(?rme, and elfewhere , thole Ponds into
which the rain-water , falling from the houfe , is conveyed
through the Common-fliores : And that they are not thereby
ever filled, but that they fwallow all that abundance of water,
that runs into them by thofe conveyances which ferve them with
water 5 infpmueh that thofe conveyances which in time of
drought maintain the Pond, when there comes new abundance
of water into the Pond, they drink it up, and fwallow it : A like
efFea might alfo fall out in the Lake, in which there being many
veins Qas it is very likely )that maintain and feed the Lake i thefe
veins might imbibe the new addition of the Rain-water , and fo
by that means annull the rifing or elfe diminifli it in fuch fort, as
to render it inobfervable. But this difficulty was eafily refolved
by cbrifidering my Treatife of the meafure of Running- Waters *
forafmuch as having demonftrated, that the abatement of a Lake
beareth the reciprocal proportion to the velocity of the Emifla-
ry^ whijh the meafure of the Sefkion of the EmiiTary of the Lake,
hath t^the meafure of the furface of the Lake : making the
calculation and account, though in grofs , by fuppofing that its
veins were fufficiently large, and that the velocity in them were
notablcin drinking up the water of the Lake yetl found never-
thelefsi that many weeks and moneths would be fpent in drink-
ing up the new-come abundance of water by the rain, fo that
I rcfted fure, that the rifing would enfue, as in effeft it did.

And becaufemany of accurate judgement, have again caufed
me to qtieftidn this rifing, fetting before me, that the Earth be-
ing pardied by the great drought, that had fo long continued, it
might be, that that Bank of Earth which environed the brink ^
the Like; being dty and imbibing great abundance of Watc*

Lib.

Of R U N N 1 N G V A T I R So

from the incrcafing Lake, would not fufFer it to increafe in
height : I fay therefore, that if we would rightly conlider thi^
doubt here propofed, we (hould, in the very confideration of it,
fee it refolved ^ for, it being fuppofed that that lift or border of
Banks which was to be occupied by the increafe of the Lake, be
a Brace in breadth quite round the Lakeland that by reafbn of
its drynefsit fucks in water, and that by that means this propor-
tion of water co-operates not inraifing of the Lake : It is aoio-
lutely neceffary on the other hand, that we confider, That tJiC
Circuit of the water of the Lake being thirty miles, as iis com-
monly held, that is to fay, Ninety thoufand Braces of t lorence
in compafs ^ and therefore adn.ictii.g for true, that each Brace of
rhis Bank drink two quarts of water, and that for the Ipieading
it require three quarts more, we fliall tiiide, that the whole agre-
gate of this portion of water, which is not implojed in the railing
of the Lake , will be four hundred ai;d fifty thoufand Quarts of
water j and fuppofing that the Lake be fixty fquare miles, three
thoufand Braces long, we fliall finde, that to difpence the water
poifeft by the Bank about the Lake, above the total furface of
the Lake, it ought to be fpreadfo thii , that one fole quart o£
water may over-fprcad ten thoufand fquaie Braces of Inrface ;
filch a thinnefs, as muft much exceed that of a leaf of beaten
Gold, and alfo lefs than that skin of water which covers the Bub-
bles of it : and fuch would that be, which thole men would have
fubftraaed from the rirtng of the Lake : But again, in the fpace
of a quarter of an hour at the beginning of the rain , all that
Bank is foaked by the faid rain , fo that we need not for the
moiftningoficimploy a drop of that water which falleth mto
the Lake. Bcfidcs we have not b/ought to account that abun-
dance of water which runs in lime of rain into the Lake, from
the fteepnefs of the adjacent Hills and Mountains which would
be enough to fupply all our occafions : 80 that, neither ought
we for this reafon to queftion our pretended rifing. And this
is what hath fallen in my way touching the confideration of the

After which, perhaps fomewhat rafhly,wandrmg beyond my
bounds I proceeded to another contemplation, which I will re-
late to you, hoping that you will receive it , as colkacd with
thefe cautions requifitc in fuch like affairs^ wherein #ve ought
not too poiltivcly to affirm any thing of our own heads for cer-
tain, butoue;httofubmitall to the found and fecurc ^^^'J^^^"
tionofthe Holy Mother-Church, as I (fothis of mine, and all
others i moft ready to change my judgement, and conform my
felfalwaies to the deliberatioRs of my Superiors. Continu-
ing

Of t^M^NSUR AT ION Lih^^

ing therefore my above-faid conceit about the rifing of the
ter in the glafs tried before, ic came into my mindc, that the
forementioned rain having been very gentle, it might well be,
that if there ihould have fain a Rain fifty, an hundred, or a thou=
fand times greater than this , and much more intenfe (which
would infue as oft as thofe falling drops were four, five or ^en
times bigger than thofe of the above-mentioned rain , keeping
the fame number) in fuch a ca{e its manifeft, that in the fpac§
of an hour the Water would rife in our Glafs, two , three, and
perhaps more Yards or Braces i and confequently, if fuch ^
Raine (hould fall upon a Lake , that the faid Lalfe would
rife , according to the fame rate ; And like wife , if fuch ^
Rain were univerfall , over the whole. Terreftriall Globe , il
would necelTarily , in the fpace of an hour , make a rU
fing of two 5 or three braces round about the faid Globe..
And becaufe we have from Sacred Records , that in the
time of the Deluge, it rained fourty dayes and fourty nights^
namely, for the fpace of ^6ohoures; its clear, that if the iai4
RaicDhadbeen ten times bigger than ours at f erw^i^, the rifing
of the Waters above the Tcrreftrial Globe would reach and paf^
amik higher than the tops of the Hills and Mountains th^t are
upon the fuperficies of the Earth h and they alfo would concui?
to increafe the rife. And therefore I conclude, that the rife of
the Waters of the Deluge have a rational congruity with natural
Difcourfes, of which I know very well that the eternal truths of
the Divine leaves have no need ^ but however I think fo clear an
agreement is worthy of our confiderationp which gives us occar
fion to adore and admire the grcatnefTe of God in his mighty
Worksvin that we are iometimes able, in fome fort, to meafdre
them by the fhort Standard of our Reafon.

Many LeiTons alfo may be deduced from the fame Doftrine,
which 1 patfe by , for that every man of himfelf may eafily know
them, having once ftabliflied this Maxime j That it is not ppflir
ble to pronounce any thing, of a certainty, touching the quantity
of Running Waters, by confidering only the finglc vulgar mear
fure of the Water without the vcldcity , and fo on the contrary,
he that computes only the velocity, without the meafure, flial^
commit very great errours for treating of the meafure of Runr
ning W^ers, it is neceffary, the water being a body, in handling
its quantity, to confider in it all the three dimenfions of breadth^
depth, and length : the two firft dimenfions are obferved by all
in the common manner, «nd ordinary way of meafuring Running
Waters j but the third dimenfion of length is omitted j and hapr
h fuchau overfight is committed, by reafon the length of Ri?a-

of Running W a t e r

ning Water is reputed in lottie fenfe infinite, in that it never cca-
fcth to move away, and as infinite is judged incomprehenfible j
and fuch as that there is no exafl: knowledge to be had thereof j
& fo there comes to be no account made thereof, but if we fliould
make ftrift refleSion upon our confideration of the velocity of
Water, we fliould find, that keeping account of the fame , there
is a reckoning alfo made of the lengthy forafmuch as whilft we
fay, the Water of fuch a Spring runs with the velocity of pafliing
a thouiaud or two thoufand paces an hour : this in fubfiance is
no other than if we had faid, luch a Fountain difchargcth in an
hour a Water of a thouland or two thoufand paces long- So
that, albeit the total length of Running water be incomprehen-
fible, as being infinite, yet neverthelelfe its rendered intelligible
by parts in its velocity. And fo much fufficeth to have hinted
about this matter, hoping to impart on fame other occafion other
more accurate Obfervations in this affair.

LAVS DEO.

F f ff

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2°K.B. 9,163

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2°K.B. 9,163

GEOMETRICAL

DEMONSTRATIONS

OF THE

MEASURE

O F

Running Waters.

B Y

D. BENEDETTO CASTELLI,
Abbot of Cassina, and Mathematician to
P. VKBAN. VII L

DEDICATED

To the moft Il/ujirms , and moft Excelknt Vrince

DON THADDEO BARBERINI.

PRINCE OF

PALESTRINA,

AND

General of the HOLY CHURCH.

L 0 N P 0 N,

Printed Anna Dm, M DC LXI.'

Ffffa

Lib,!.

OF T H E

MENSURATION

O F

' Running Waters.

SUPPOSITION I.

1 — ^

Etitbefuppofed,that the banks of the Rivers of which
we fpeak be ereaed perpeqdicular to the plane of the up-
per fuperficies of the River.

sUPP05iI.3E|bN II.

WE fuppofe that the plane oT the bottome of the River, of
wbi^h W{.fpc»k-W .atjighi angks with the banks.

supAsifioi^ uiv

,T is to be fuppofed, that we fpeak of Rivers, when they arc at
Jcbbe,inthatftateof fliallownelTe, or « flowing •n;'^""*"
of deepnffe, andno^, ip their tranficion from the cbbc to tbe
f|ftWing» or fr-^"> the ftpwingto the ebbe.

. 3'!^ •Q^aFamtn af Ttrmes.

TF a River '{hall be cut by aVkne.at right angles to the furfece
lof the water of the River, and to the banks of the River,
that fam div^ing Plane ^e call theSedion of the River, and
this Seaon, by theiuppofitions above, ftall be a right angled
ParaUelogram.

velocity. ^ ^

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2°K.B. 9,163

Of M EN S U R A T ION

AXIOME

CEfliotj^equaJ, and equally fwift, direharge equal quantities
^of w4 ter in ^qual times.

AXIOJyIE, II.

SEfiions equally fwift, and that difcharge equal quantity of
Watei;^ in equal time jfhall be ec|ual.

AXIOME III.

CEftions equal, and thit difcharge cqditl^dantities of Water
^iil equal tirncs^ fliall be equally fwifc.

WHen Se&ions are unequal, but equally fwift, the quanti*
ty of the Witer that pafTeth through the firft Seftion,
fliaj! have the lame proportion to the quantity that paf-
feth through the Second, that the firft Setai(>ft hath (b the fecond
f'i(»n. WhidK is mauifc-ft , becaufe^ thb velocity being the
faille, the difFel?ncc of the Water that palTeth (hall be according
to theditlerenceof-theSeaions. " '

■ A XIOM E V. - i I

If theSeflions (hall be equal, and of unequal velocity, th^'
quandcy ot the Water that paffeth through the feft, (hall
have f^ie fame proportion to that which palTeth through the
fecoad, that the velocity of 'the firft Sedion, fliall have to the
Vk loci- y of the fecond Scftion. Which alfo is manifeft, becaufc
the Stations being equal, the difference of the Water which
pa(rcth, dep^ndetb oh the velocity.

PETITION.

A Sefiion of a River being given, we may fu^^ipofe anotheif
equal to the given 5 of different breadth, heigth, and ve-
locity.

PRO-

ATS It I

Lib.i.

pftOPOSJTI

TheSeBionsofthe fame^her dif charge equal qmn-
tities of Water m equal times, although the Secti-
ons themfehes he unequal.

LEtthetwo Seaionsbe A and B, in the River C, running
from A, towards B ; I fay, that they difcharge equal quan-
tity of Water in equal times i for if greater quantity 6f Wa-
ter (hould pafs througli A, than paffeth through B, it would

follow that the Water in the intermediate fpacc of the River C,
would increafe continually, which is manifeftly falfc, bat
more Water fhould iffue through the Seaion B, than entreth at
the Seftion A, the Water in the intermediate fpace C, would
grow continually Icfs, and alwaies ebb, which is likewife falfe i
therefore the quantity of Water that paffeth through the Scfti-
onB, ii equal to the quantity of Water which paffeth through
the Seaion A, and therefore the Seftions of the fame River dif-
charge, &'C. Which was to be dcmonftrated.

pROPOStTlON II.

In tWoSeBions of ^iyers, the quantity ofthel^ejr
ivhich paffeth by one SeBion, is to that wichpaj-
fethby thefecondjn a 'Proportion compounded of
the proportions of the frfl SeBion to the fecond^nd
of the yelocitie through the frS^ to the yelocitie
ofthefecond.

LEt A, and B be two Seasons of a River i Ifay , that the
quantity of Water which paffeth through A, is to that which
paffeth through B, in a proportion compounded ot the pro-
portions of the firft Seaion A; to the Seaion B ; and ot the Velo-
city through A, to the velocity through B : Let a Seftion be.

(uppofea

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Of tbt Mf NSUIVAT IOJI

till

fuppofed equal to the Sefiion A, in ipagnitudc ^ but of velocity
equal to the Sefiidn and let it be G \ and as the Seftion A

[

to the Section B> fo let the line F be to the line D , and as the
velocity A , is to the velocity by B, fo let the line D be to the
line R : Therefore the Wate r which pafleth thorow A^fliall be
to that which paffeththiough G (in regard the Sc6ionsAand
Gareofcqualbignels, but of unequal velocity) as the velocity
through A, to the velocity through G ; But as the velocity
through A,is to the velocity through C , fo is the velocity through
A, to the velocity through B 5 namely, as the line D , to the
lineR : therefore the quantity of the Water which paffc the
through A, fliall be to the quantity which palTeth through G, as
the line D is to the line R ^ but the quantity which pafleth
through G, is to that which pafleth through B, On regard the
Seaions G, and B, are equally fwift) as the Sefiion G to the Se«
aionB ? that is, as thcSeaion A, to the Se^ion that is, M
the line to the line D ; Therefore by the equal and perturbed
proportionality, y he quantity of the Water which paflbth through
A, hath the fame proportion to that which pafleth through B,
that the line F hath to the line R j but F to R , hath a proportion
compounded of the proportions of F to D, and of D to R ^ th^t
Is, of the Seiiion A to the Seftion B jand of the velocity through
A, to the velocity through B .• Therefore alfo the quantity of
Water which paflVth through the Seftion A,(hall have a propor-
tion to that which pafllth thrc ughthe Sefiion Bx compounded of
the proportions of the Seflion A, to the Scftion B , and of
the velocity through A , to the velocity through B: And
therefore in two Seftions of Rivers, the quantity of Water wbi^ih
pafleth by the firftvd^^^. which was to be demonftratcd,

COKOLL ARIE.

^He fame foHoweth, though the quantity of the Wat.er whi^b
.paflbth through theSeaion A, be equal tp the quantity pf
water which pafleth through the Sedion B, as ii manifeft by the
tame demonftiation. p R O P

Lfb.il Of RuNiaikG Waters*

PROPOS ITION lit.

In tT\^o SeBions unequal o through yphich pafs equal
quantities of Water in equal times ^ the SeBions
hay e to one another^ reciprocal proportion to their
yelocitie.

LEc the two unequal Seftions, by which pafs equal quantities
of Water in equal times be A, the greater *, and B, the leffer:
I fay, that the Seciioii A, (hall have the fame Proportion
to the Scdion B, that reciprocal :y the velocity through B, hath to
the velocity through A, for fuppolmg that as the Wafer that
pafTeththrough A, isto that which paffeth through B, fo is the

iiuc Eto-thq lincF : therefore the quantity of water which gaf-
ferii through A, being equal to that which paficth through B,
the line E fliall alfo be equal to the liiie F : Suppofing moreover,
That as the SeSion A, is to thc SeAion B, fo is the line F, to the
line G and becaufe the quantity of Water which paifetH
through the Scftion A, is to that which paffeth through the
SefiionB, in a proportion compofcd of the proportions of the
Seftion Aj to the Seftion B, and of the velocity through A, tt> thp
velocity through Bi therefore the line E,{hall be the hne to F,in
a proportion compounded of the fame proportions *, namejy, of
the proportion ot the Seftion A, to the Section Bv^nd of the ve-
locity through A, to the velocity through B h but the line E, hath
to the line G , the proportion of the Seftion A, td the SeSion B,
therefore the proportion remaining of the line G, to the line F,
fhall be the proportion of the velocity through A, to the velocity
through B j therefore alfo the line G, fhall be to the line E , as
the velocity by A, to the velocity by B : And converfly5the ve-
locity through B5 fliall be to the velocity throujgh A, as the . line
Ej to the line G j that is to fay, as the Seftion A, to the Seftion B,
and therefore in two Seaions,&c. wbtchwas to be demonftrated.

Gggg COKOL^

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€f^be MENSORAt ioK Lib h

t 60K0LL ARIE^

Hl^nq^itis inariifeft^ that Sdaions of the fanie River (which
are.^o other than the vulgar meatiires of the River) have
betwixt themfelves reciprocal proportions t6 thbir veloci-
ties i» For in the fitft Propofitiori Vve have demonftrated that the
Sections of the fame River, difcharge equal quantities of Water
in equal times ^ therefore, by what hath now been demonftrated
the Sections of the fame River fliall have reciprocal proportion
to their velocities ^ And therefore the fame running water chan*
gcth m^fure, when it changeth velocity i namely, increafeth the
meafure, when it decreafeth the velocity , .and decreafeth the
meafur^5 when ic increafeth the velocity.

On >A^hich principally depends all that which hath beeii f id
above in the Difcourfe^ and obferved in the Corollaries and ylfp*
pefuUxes 5 and therefore is worthy to be well underftood and
heeded.

PROPOSITION IV.

If a 'J^iyerfall mo another ^iyer^ the height of the
jirjl m Its own Qfm^^ J^^^^ ^^^^ height that it
(hall make in the fecond Qhaneh m a proportion
to^pounded of the proportions of the breadth of
fh^ Chanel of the jecond:, to the breadth of the
• f^anel of thefirji:, and of the yelocitie acquired in
C^^anet of the fecond , to that T^hich it had in
Mtiproper and frsf C haneL

tcEcAc R'iv^r A B, whofe height is - A C, and breadth C B ,
1 that is' whofe Seflion is A C B *, let it enter, I fay, into a-
- 'nbtber Riv^r as broad as the line E F, and let it therein make
the rife or height D E, that is to fay, let it have its Seflion in
the Ri^erwhereinto it falls DE F 5 I fay, that the height AC
Hath to tire height D E the proportion compounded of the pro-
port of the breadth E F, to the breadth C B, and of the ve-
locity through D F 5 to the velocity through A B, Let lis fup-
pofe rheSeftionC, equalin velocity to the Scftion A B ^ and in
breadth equal to E F, which carrieth a quantity of Water c-
qual to that which the Scftion A B carrieth, in equal times,
and cohftquciitly, equal to that which D F carrieth. Moreover,
is the breadth E-V is to thebreadth C By fo let the line H be t<^

the

(9/ Running VVAtERs.

the line I and as the velocity of D F is to the velocity of A
fo let the line I be to the line L '5 becaufe therefore the two
Sefiions A B and G are equally fwift, and difcharge equal quan*
tity of Water in equal times, they fliall be equal Seftionsj and

therefore the height of A B to the height of G, fliall be as the
breadth of G, to the breadth of A that is, as E F to C
that is, as the line H to the line I : but becaufe the Water which
paffeth through G, is equal to that which pafTeth through D E F,
therefore the Scfli on G, to the Seftion D E F, fliall have the re-
ciprocal proportion of the velocity through D E F, to the velo-
cicy through G , but alfo the height of G, is to the height D E,
as the Seftion G, to the Seftion D E F : Therefore the height of
G, is to. the height D E, as the velocity through D E F, is to the
velocity through G i that is, as the velocity through D E F, is to
the velocity through A B j That is, finally, as the line to the
line L , Therefore, by equal proportion, the height of A B, that
is;, A C, fliall be to th^ height D E ^ as H to L , that is, com-
pounded of the proportions of the breadth EF, to the breadth
C By and of the velocity through'D F, to the velocity through
A B : So that if a River fall into another River, &c. which wa*
to be demonftrated.

Gggg 2

PROPO.

Of fhi M e'n s u Tx a t I o

PROPOSITION V.

If a ^yer dijchargc a certain qmmitie of iter
in a certain time ; and after that there come into tt
a Flood, the quantity of IFateriphich is dtf char-
ged in much time at the flood, is to that ypmch
TPas dif charged before, Mji the ^lyer TPas loW,
in a proportion compounded of the proportions of
the 'velocity of the Flood, to the velocity of the first
Water , and of the height of the Flood , to the
height of the first Water.

SUppole a River, which whilft it is low, runs by the Seaion
A F i and after a Flood come rh into the fame, and runneth
through the Seaion D F, I lay, that the quantity of the Wa-
ter which is difcharged through D F, is to that which is difcharged

7." 'ijir.V7 '.ub tsiui.

through A F5 in a proportion coihpounded of the proportions 6f
chfSrVeiocity through D F, to the velocity through AF,' and 'of
th^ height ;D By to the kcfight A B h As the velocity through DF
is to the. vielocity through A F, fo let the line R, to the liileS j
and as the height D is to the height A fo let the line S, th
the line T j and let us fuppofe a Seaion L M N, equal to D F
in height and breadth^ that is L M equal to D B, and M N equal
to B f 5 but let it be in velocity equal to the Seaion A F5 there-
fore the quantity of Water which runneth through D F, (hall be
to that which runneth through LN, as the velocity through DF,
is to the velocity through LN, thatis, to the velocity through
J F y aif4 the line R being to the line S, as the velocity through
b F, to the velocity through A F ^ therefore the quantity which
runneth through D F, to that which runneth through L N, ft^I^
have the proportion of R to S ; but the quantity which runneth
through L N, to that which runneth through A F, (the Sedions

being

Lib. i. f)/ U N N I ia G W a t e r is.

being equally fwift) ftiall be in proportion as the SeSion L N, to
tlie Seaion A F ; that is,as D B,to A Bj that is as the line S , to
the line T: fherefore by equal proportion, the quantity of the
water which runneth through D F,(hall be in proportion to that
which runneth through A F,as R is to that is, compounded of
the proportions of the height D B, to the height A B, and ot the
velocity through D F,to the velocity through A F ,and therefore
if a River difcharge a certain quantity, which was to be de-
monftrated.

Annotation.

THe lame might have been demonftrated by the fecond
Propofi ion above demonftrated, a:, is maniteft.

, PROPOSITION VI.

If two equal firedms of the fame Torrent, fall into '
^tver at dh>ers times, the heizhts made in the
-ver the T orrent , [hall have befWeen them-
fehes the reciprocal proportion of the -velocities
acquired in the l^tyer.

LEt A and B, be two equal ftreams of the fame Torrent,
which falling into a River at divers times, make the heights
C D, and F G ; that is the ftream A, maketh the height
CD,andthcfticam B,maketh the height F G ' that is, Let
their Seaions in the River, into which they arc fallen, bcCE,
andF H i I fay, that the height C \\ Oiallbe to the height t O,
in reciprocal propo tion, as the velocity through F H, to the ve-
locity through CEiforthc quantity of water which paffeth
through A, being equal to t^^^^^^^^^^

R 1
^ 1

r ^

I-

,h,„„gh C E . Bu. .h= ea,0 C E .. » h^^^^^ . ^^^^^^^

I S' Ml b= » „ Sproc" 1 propo-cio. .he velocity
SrSsK H i to the velocity throogh C E...>d therrfco ,t »o
e,u"l ftreams of the fame Torte„t, which was to be ^
monftrated.

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2°K.B. 9,163

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2°K.B. 9,163

Lil7.2.

OF T H E

MENSURATION

O F

Running Waters.

II.

Aving, in tK- clofe of my Treaitiie of the
Meiifuration of Running Waters jprotnifcd'
to declare upon another ocufidn Other par-
ticulars more obfcure , and of very great
concern upon the farhe irgurtieth'^nfrl iloW
do perfofnii my promifc on thfe occafion
that I had the jiaft year 1^41 . to propound
my thoughts touching the ftate of the Lake
of Venice, a bufinefs certainly mpft importaHt, as being the
concernment of that moft ribble and moft adfflirablc Cty ; and;
indeed of all Iialy, yea of all Enrofe, Afia,Sc Africa i Scone may,
truly fay of all the WholeWorld.And being to proceed according
to the tritthbd necete'ry in Sciences,! wil jpropole,!!! the firft place
certain beenicions of thofe Terms vwheteof: we arc to ntoke ufe
in our DJfcbUrfe PUkd ffien, liyiilg dov^n " Certain Prf*abtes «re
will de nonftratc fomc Problcmcs and Theoremes ncccffary for
theund-n ftandingof thole thin^. which w« are to deliver i and
.Moreover, recounting fundry iale/rl^at have happened , we will
prove by pradice, what utH.cy thu contemplation of the
Mcafurc bf ^Runliin2i/^fos is;g tfe more uhportant affairs both
PHblicpj^^itidPrf^ ''.-iaiiiai

D E t liNit iON 1. .
T-WuUivers ak- fkidVo Wv^ wJth equaf Velocity, whenin c-
* qual times they palfe fpaces of equal leiiph. ^ . _

Elvers arc laid to move vv.itb:ltk:e.vel6city,v}hen their prot-or-
tional parr, d;>..tvovc alikcvtlf i.v the upper par^^^^^^^^
th. upper, and the lovver to the lower •, to that .f the upper
part of one River (luW be more fwifc than the upper part ot ano-
Lri then alfo the lower part of the former (hall be more fwift
than the part correfpondent to it in the lecond, ptopottio^aU^. ^

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2°K.B. 9,163

* Or Sluice.

DEFINITON III.

TrO'mlafure a Pvivei , or running Water, is in oiir fenfe to finde
out how many determinate mealures ^ or weights of Water
in a given time paffeth through the River, or Channel of the
Water that is to be meafured.

DEFINITION IV.

IF a Machine be made either of Brick ^ or of Stone , or of
Wood, fo compofed that two fides of the faid Machine be
placedat right angles upon the ends of a thiid fide, that
fuppofed to be placed in the bottom of a River , parallel to the
Hori2on,.]in Tuch a manner, that all the water which runnetb^i
through^ the faid River, paffeth thorow the faid Machine : AnS
if alj th^ 'vvacer comi to be diverted, [

Gr p

thac^runnieth through the faid River, the
4P{jer ruperfi.cies o^ that third fide placed
in th^ bc^tom do /remain uncovered
aiiid dr^^ Wid that the dead water be not

abbyc:it 3: XWs fame Machine fliall be

cijl^^ ;&y us * R E G u L A T o R : Aud that third fide of the
Machine which ftandeth Horizontally is called the bottom of
the j^^iplatorb and the other two fides, are called the banks of
the Regulator as is fcen in this firft Ftguie : A B C D, ihall be
ti^e Regulator , B C the bottom ^ and the other two fides A B,
and Q.j^jare its banks. '

. D EFINlTIOf^;^^^^^

B%}MW rtiean tl^'e Perpeii<iicufar ifrorh

luperficics of thtKiver,unto the Upper fuperficies of the bot-
tom of the Regulator j as in the foregoing Figure the line. G H.

definit.i6n yi.

JFthe water of a River be fuppofed to be marked by three
fides of a Regulator, that Rightangled Parallelogram compre-
hendedbetween the banks of the Regulator, and the bottom,
and the fuperficies of the Water is called a Seftion of the

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2°K.B. 9,163

lik 7-

Of R u n Kin G Water s.

ANNOTATION.

HEre it is to be noted, that the River it felf may have fundry
and divers heights, in feveral parts of its Chanel, by reafon of
the various velocities of the water , and its m#fures ^ as hath
been deinonftrated in the tirft book.

SUPPOSITION I.

J T is luppofcd, that the Rivers equal in breadth , and quick
heif^ht, that have the fame inclination of bed or bottom , ought
alfo To have equal velocities, the accidental impediments being
removed that are difperfed throughout the courfe of the water,
andabftrafting aUb from the external windes, which may velo-
and retard the coucfe of the water of the River.

cita'te, ar

SUtPOSlTlOlSi It.

f Et us fuppofe alfo, that if there be two Rivers that are iii
*^their beds of equal length, and of the fame inclination > but of
quick heights unequal, they ought to move with like velocity^^

according to the

jnfe explained in the fecond definition.
SUPPOSITION lit

BEcdiile it will often be requitite to medfarc the time exafitly
in the f Jlfowiog Prot>lcnis , we take that to be an excellent
way to mcaUu-c the time, which was fliewcd me many years fince
by Si^^^^rc GaliUj GjUIxi, which is as followeth. _ .

A firing is to be taken three Romari feet lon^, to the end 6£ '
which a B^illctof Lead is to be hanged, of about two or^three
ounces^ and holding it by the other end, the Plummet is 'to be
removed from its perpendicularity a Palm, more or lefs, inS. then
let ^o, which will ma.ke many fwings to and again , paffing and
repairing the Perpendicular, before that it ftay in the fame : Now
it bping reqLured to meafarc the time that is fpent in any what-
foe/er operation, thpfe vibrations arp to be 'numbred , that are
made vfhWa clic worklaftcth ; and they (liall be fo many fecond
minutes of an hour, if io be,that the firing bp three Roinan feet
loiig , but in (tioL tcr ftrinfi^s, the vibrations are more frequent, and
in longer, lefs frequent ^ and all this flill followeth, whether tht
Plummet be little or much removed from its Perpendiculariityj^jr
whether the weight of the Lead be greater or lefTer.

Thel^ thinc^s beinc^ pre-fuppofed, we will lay ddWn fonie
> . 5.i4 ^ Hhhh tniVtit

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Of the Mensuration. Lib2\

miliar Problems, from which we ftall pafs to the Notions and
queftions more fubtil and curioub ^ which will alfo prove profi-
table, and not tobefleighted in this bufinefs of Waters.

PROPOSITION L PROBLEME L

J Chanel of ^unmng-IVater being gmn,the breadth
of -which pajsing through a Regulator , is three
Talms; and the height one Talm, little more or
lefs. , to meafure what Water pafeth through the
^et'uhtor in a time given.

FIrft, we are to dam up the Chanel , fo that there pafs not any
water below the Dam ; then we muft place in the fide ot the
Chanel, in the parts above the Regulator three, or four, or five
Bent-pipes, or Syphons;according to the quantity of the water
that runneth along the Chanel in fuch fort, as that they may
drink up , or draw out of the Chanel all the water that the Cha-
nel bearetti (and then fliall we know that the Syphons drink up
ti^ Water, when we fee that the water at the Dam doth mi*
ther hfc higher, nor abate, but alwaies keepeth in the fame Le-
vel.) Thefe things being prepared, taking the Inftrument to
meafure the time, we will examine the quantity of the water that
iffueth by one of thofe Syphons in the fpace of twenty vibrations,
and the like will we do one by one with the other Syphons j and
tljen collefiing the whole fumme, we will fay , that fo much is
the ^ater that palTcth arid runneth thorow the Regulator or
Chanel (the Dam being taken away) in the fpace of twenty fc-
cbnd minutes of an hour j and calculating, we may eafily reduce
4t t9 hours, daycs^ months, and years : And it hath fallen to my
tiirii'tb meafure this way the waters of Mills and Fountains, and I
h^vebecn well affuredof its exaSnefs, by often repeating the
fai^e work.

CONSIDERATION.

fsid this method muft be made ufe of in meafuring the waters,
thfit we are to bring into Condufts , and carry into Cities
and iCaftles, for Fountains j and that we may be able afterwards
to divide and (hare them to particular perfons juftly ^ which will
prevent infinite fuits and controverfies that every day happen in
Aefe matters..

propo-

L ib. 3,

(?/ R a N N I N G W A t E R S^;

H
F

PROPOSITION II. THEOREM I.

If a ^yer moymg wkb fuch a certain yelocitie
through its Regulator ^ /hall haye a giyen quicks
height^ and aftermrdsby neT^ypater[hall iffcreafe
to be double , it fhall alfo increafe 'double in ye-
locitie.

LEt the quick height oif a River in the Regulator A B C D,
be the perpendiailar F B, and afterwards,by new water that
is added to the River , let the water be fuppofed to be raif-
ed to G, (o that G B may be double to E B. I fay, that all the
water G C fliall be double in velocity to
that of E C : For the water G having
for its bed the bottom E F, equally in-
clined as the bed B C, and its quick
height G*E being equal to the quick
height E C,and hiving ihe fame breadth
B C, it (hall have of it felf a velocity e-
qual to the velocity of the firft water
EC: but becaufcjbefides its ovirn moti-
on , which is imparted to it by the motidn of the water E C, it
hath alfo over and above its own motion^the motion of E C.And
becaufe the two waters G C, and E C, arc alike in velocity, by
the third Suppolition , therefore the whole water GC fliail be
double in velbcicy to the water E C 7 which was that which We
were to demonftrate.

This demonjiration is not here infeHcd^as perfe5i^ the Authour ha-^
r^ing by federal letters to his friends confejfed himfelf nnfatisfU
ed therewith \ and that he intend e-d not to fubltjh the Theoreni
without a i^tore folid demonjiration^ which he was in hope to light
upon. But being o^ertal{en by Death , he could not gi^e the
finifiing touch either to ihis^ or to the reH of the fecond Book* In
confide ration of whuh^ it feemed good to the Publijher of the
fame^ rathei to omit it^ than to do any thing contrary to the mind of
the Authour. And this he hints^ byway of adi/ertifentent , to
thofe that have Mamtfcript Copies of thk Book, , tsfith the faiddc^
ntonjiration. Fot^this time let the Reader content himfelf tPith
the knowledge offo ingenious and profitable a Conclufioa , of the
truth of which he may, with fmall expence and much pleafure^ ht
ajfUred by means of the experiment to be made in thi famentan^
n^r , iPtth thai which is laid down in the fccmd CorgUan

H h h h 1 tbi

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Of fi&e M E N S U R A T I O N Ltb. C

the fourth Thcoicm of thk , nptth its 7 able, andthenfcthere^
of annexed.

COKO LLAKIE

HEnce it foUpweth, that when a River increafcth in quick
- height by the addrtibn of new water, it alfo incrcafethin ve-
locity fo that the velocity hath the fame proportion to the velo-
city that the quick height hath to the quick height ; as may be
demonftrated in the fame manner.

ii^ljT^^AlOPOS. 111. PROBLEME I L

• - .J .

A Chrxhfl^ater being given n^bofe headtb exceeds
twenty Palms, or tl ereabouts , and whofe qmc\height
is Ufs than five Valms y tdmeafun th e qnantity of the
Water that runneth thm^ the Qhanel in a time
given.

PlLacemthcChahel a Regulator , and.obferve the quick
height in the faid Regulator s then let the water be turned
away from the Chanel by a Chanellet of three or four Palms
ki bread ch> or thereabouts ; And that being^done, meafure the
q[uaAui|y ,4tf the water which paifeth thorow the faid Chanellet^
as hatjij taught in the fecond Propofition , and at the fame
time p^jerve exaftly how much the quick height lhall be abated
in ihii greater Chanel, by means of the diverlion of the Chanel-
let j and all thefe particulars being performed, multiply the quick
height of the greater Chanel into it felf, and likcwife multiply
iiicpitfelf the lelfer height of the faid bigger Chanel, and the
leii^.iqi^re being taken, from the greater, the remainder fliall
have tlie:famc pipportion to the whole greater fquare, as the wa-
t^r of the GhanelJet diverted , hath to the water of the bigger
Chanel : And becaufethe water of the Chanellet is known by
the Method laid down in the firft Theorem, and the terms of the
Theorem being alfo known, the quantity of the water which run-
xveth thorow the bigger Chanel, fliall be alfo known by the Gol-
den Rule, which was that that was defired to be known. We
will explain the whole bufinefs by an example.

Let a Chanel be,forexamplc,i 5 Palms broad, its quick height
before its diverfionby the Chanellet ftiall be fuppofed to be 24
inches vbut after the diverfion, let the quick height of the Chanel
l>eonely 2 a inches. Therefore the greater height to the leffer,
is as the Bumber 1 1 . to 1 2 .But the fquare of i i . is 1 2 1 , and the
V^iaare of 12. is 14.4., thcs difference between the faid lefTcr

Likil Of Running Waters.

fquare and the greater is a 3. Therefore the diverted water, is
to the whole water, as 23. to 144 : which is well near as i to
6 -A : and that is the proportion that the quantity of the water
which rurtncch through the Chanellet fliall have, to all the water
that runneth thorow the great Chanel. Now if we fliould finde
by the Rule mentidned above in the firft Propofition , that the
quaniity of the water that runneth through the Ghanellet , is
0,g^ an hundred Barrels, in the fpace of i^fecond minufcs of
an hour, it is manifeft, that the wati^r-which runneth through the
greatChanel in the faid cime of 35 min. fee. (hall be about 600
Barrels. - ' " ^ : O ^

thx fmf: operation verfpm^i f^ffiftkerway.

ANdbecaufevery often in appmpg the tteo^^ to PraSice
it happ^^ieth, that al: chc neCeliliy particulars in the . The-
• ory canhotfoeaffly'bc j^t iaixecutioiii therefore we^ will
here add another way 0^' periorniiiig the fame Problem , if it ft^u Id
chance to happen that the GhancUet could not commodioufly be
diverted from the great Chanel, but ^ that it were eafier fbr the
water of another fmaller Chanel to be l;)rouglxt into the greater
Chanel which water of the fmaller Chanel might be eafily mea-
fured as hath been flicwen in the firft Probleme j or in cafe that
there did fall into a greater Ghand^ a leffer Chaoel that might
be diverted and meafured. Thercfiajie 1 fay .inithe firft cafe,- If
we would meafure the quantity of the water that runneth in a
certain time thorow the greater ChaBeh into which another ^Idfler
Chanel that is meafiuaWe may be brought, w« muft firft CBcafily
meafure the Chanellet, and then obfcrve the jquidi height of the
greater Chanel, before the introduftion of the leflcr j and having
brought in the faid Chanellet , we muft agnin find the propiir.
tion that the water of the Chanellet hath to all the water ot the
great Chanel for thefe terms of die proportion being known, as
alfothe quantity of the water of the Chanelkt , we fliall ajfo
come to know the quantity of the water that runneth thorow.
the^reat Chanel. It is likewife manifeft , that we fliall obtain
our intent, if the cafe were thit there entered into the great
Chanel^ another lelTer Chanel that was meafurable , and that
might be diverted.

CONSIDERATION.

IT would be neceffary to make ufe iof this ^Doarine ifl the jdi«
•* ftribution of the waters that are tiaploy'd to overflow the fields,
as is ufed in the Brefciari^ Crenu)jkfe^.'Bet§amaft^ LodigiaO^^-

ftefe,

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Of the M E N s u p. A T I o t4 Lib. ^

nefe territories, and many other places, where very great fuics
and differences arife, which not being to be determined with in-
telligible realbns, come oftentimes to be decided, by force of
armes , and inftead of flowing their Grounds with" Waters^ they
cruelly flow them with the (liedding of humane blood, impioufly
inverting the courfe of Peace and J ufticc, fo wing fuch diiorders
and feuds^ as that they arc fometimcr^ accompanied vvith the ru-
ine of whole Cities, orelfe unprofitably ch^'.rge. tljifcm with vauij
andfometimes prejudicial expences.

PROPOS. IV. THEOR. II.

If a ^iyer increase in quicks height , the quantitie of
Water "Which the ^her difchargeth after the in-
creafer> hath the Proportion compounded of the

\ Proportions of the QutcJ^ height to the Quicks
heighto and of the velocity to the velocity.

LEt there be a River, which whilfl: it is low, runneth thorow
the Regulator D F, with the Ciiiick height A B, and after-
wards let a Flood come^ and then let it run with the height
DB y I fay, that the quaritity of the Water that is discharged
through D F, to that which difchargeth through A F, hath the
proportion compounded of the proportions of the velocity
through 13 F to the velocity through A F, and of the height
D B to the height A B. As the velocity through D F is to the
velocity through A F, fo let the line R be to the line S j and as
the Jicight D B is to the height A B j fo let the line S be to the

in ■:■ ! l' j'

A-

S
T

M_ -N

line T, And let a Seftion be fuppofed L M N equal to the
Sefiion D F in height and length, but let it be in velocity equal
to the Scftion A F. Therefore the quantity of the Water that run-
neth through D F to that which runneth through L N, ftaJl be

Lib^'i* 0/^ Running Waters. 5'^

as the velocity through D F, to the velocity of L N, that is, to
the velocity through lN, that is, to the velocity through A F.
therefore the quantity of Water vi'hich runneth through D
to that which patTeth through L N, fliall have the proportion
thatRhachtoS ^ but the quantity of the Water that runneth
through L N, to that which runneth through A F i (the Sc&ions
being equally fwift) (hall have the proportion that the Sefl^ion
L N hath to the Seftion A F, that is, thit the h-ighc B D hath to
the heiaht A5 that is, that S hath to T. Therefore, by equal
proportion, the quantity of the Water which runaeth by D f ,
to that which runneth by A F, (hail have the pro^>ortion 01 il co
T, that is, (hall be compounded of the proportions of the height
D to the height A B h and of the velocity through D F, to
the velocity through A F. A id therefoie if a River incrcafe in
quick height, the quantity of the Water that runneth after the
increafco to that which runneth before, the increafe , hath the
proportion compounded, &c. Which was to be dem^aftratcd,

COROLL AKIE I.

HEnce it followeth, that we having (hewn, that the quantity of
the Water which runneth, whilft the River is high, to that
which ran , whilft it was low, hath the proportion compounded
of the velocity to the velocity, and of the height to the height.
And it having been demonftrated, that the velocity to the velo-
city is as the height to the height 5 it followeth, I fay, that the
quantity of the Water that runneth, whrlft the River is high, to
that which runneth, whilft it is low, hath duplicate proportion of
the height to the height, that i$j the proportipn thar the fquare^
of the heights liave.

CO KOLL AHIE IL

VPqn which things dependeth the reafon of that which I have
faid, in my fecond Confidcration, that if by the diverfion of
{ of the Water that entereth by the Rivers into the Moor or
Fen, the Water be abated fuch a meafure, that fame ihall ^bc
only one third of its whole height^but moreover diverting the \ it
jhall ab^te two other thirds^ a moft principal point j and fuch,
tb^t its not having been well underftood, hath caufed very great
difoiders, and there would now, more than ever, follow extream
dammagc, if one fliould put in execution the diverfion of the SiU
and other Rivers ^ and it is ttfanifeft, that in the fame nunner,
wherewith it hath been demonftrated, that the quantity of tin?
Water increafing quadruple, the height would increafe andy

ddubtcs

0/ MeNSIi RAT 10 N Li^?.2,.

dbuble, and the quantity incrcafing liOnuplc, the height incrca-^
feth triple fo that, by adding to units all the odde numbers, ac*
cording to their Series, the heights increafe according to the na-
tural progreffion of all the numbers, from units. As for exam-'
pie, there paffing thorow a Regulator fucha certain quantity ot
Water in one tirtie*, adding three of thofe meafures , the quick
height is two of thofe parts 5 which at firft was one*, and con-^
tinning to adde five of thofe faid mcafuresjthe height is three of
thofc parts which at firft were one j and thus adding feven , and
then nine, and then i i- and then t 3, &c the heights (hall be 4.
then 5, then 6. then 7, &:c. And tor the greater facility of the
Work, we have defcribed the following Table, of which we will
declare the ufe : The Table is divided into three Series or Pro-
greffions of Numbers : the firft Series contaSncth all the Num-
bers in the Natural Progrcfliop., beginning at a Unit, and is called
the Series of the Heights , the fecond containeth all the odde
numbers,*beginning at an unit, and is called the Series of the
Additions: the third containeth all the fquare numbers, begin-
ning at an unit, and is called the Series of Quantity.

1' jHcight^ 1 I 1 al 3I 4I $1 61 7I 81 gl lol ii|
lAdditions. 1 il 3I 5I 7 1 pTiTTi3 1151171 i^l 2ij
louantities.l il 4I 9 h6 [25 I36 I49 164 181 liooli a i )

The ufe of the afore- mentioned Table.

Firft, if vve fuppofe the whole quick height of a kiver of Run-
ning Water to be divided into any number of equal parts, at
pleafure, and would abate the fame one fife, by means of a divi-
(ion j let there be found in the Table in the Scries of heights the
number 5. the denominator of the part which the River is to a-
bate, knd'take the number that is immediately under it in fhe
row of Additions, which is 9. which let be fubft rafted from the
number 25. placed underneath the fame in the row of Quanti-
ties, the remainder i fignifieth that of the 25. parts of Water
fhat tan in the River, whilft it was 5 meafures high , there do
onely run 16. parts ; fo that to make it abate y it is neccflary to
take 1? from the Water that the whole River did carry fo that
With fubftrafting fomewhat more than one third of the Water of
the Rivc^', it is abated but duly one fift.

' And rTin?, in the fecond place, if on the contrary, one would
know hovif much Watei* is to be added to the faid Aivcr to niaike
itincre^tfc onefift inoreinh^^ fo as that it may rdn in the

Regulator

Lih.-i. (9/ Running Water $.

PveguUtor 6. of thofe parts high i of which it ran before but 5. let
6 be found in the row of heights, and let the number li. ftand-
ing under the fame be taken and added to the number 25.
that is placed under the number 9. in the Additions , and 5." in
the heights, and you fliall have 36^ which is the quantity of the
water that runneth with the heightof the River, when it is high
6 of thofe parts, whereof it was before but 5 .

2. But if it ihould be defired, to know how much water it is
requifite to add to make the River rife fo, as that it may run in
heights, of thofe parts of which before it ran but 5 ; one
ouaht to take the fum of the number of the Series of Additions
(landing under 8. 7. and 6, which are 1 5. 1 3. and 1 1. that is, 39.
and this fliall be the fumme that muft be added to 25 : So that
to make the River to run 8. of thofe parts in height, of which it
before did run 5, it will be ncceflary to add 39. of thole parts,
of which the River before was 25.

A. Likewife the fame Table giveth the quantity of water
that runneth from time to time through a River, that increafeth
by the addition of new water to the fame in one of its heights, the;
quantity of its water be known. As for example: If we knew that
the River in one minute of an hour difchargeth a^oo.of thofe mea-
fures of water,and runneth in height 5. parts in the Regulator,and
afterwards fliould fee that it runneth 8 Palms high , finding m the
row of quantity the number placed under S.which is 64. we would
fay that the River heightned, carrieth of water 64. of thofe parts
whereof it carried before but 25 i and beeaufe before it carried
a -5 00. meafures, by the Golden Rule we will fay.that the River
carrieth 64oo.of thofe meafures,of which before it carried 3 500.

in this progrefs of Nature, is one thing really curious, and that
at firft fiaht leemeth to be fomewhat Paradoxal , that we pro-
ceeding ordinatcly in the diverfions and additions , with additi-
ons and diverfionsfo unequal, the abatings do notwithftandmg
alwaies prove equal, and fo do the tifings : And who would ever
think that a River in height, c/.^. 10. Palms, running and carry-
ing an hundred meafuies in a minute of an hour, is to abate but
one Palm, onely by the diverfion of 19- of thofe meafures i and
then aeain, that the buifinefs cometh to that pafs , that it abateth
likewife a Palmby the'diverfion of three onely of thofe mealures,
nay, by the diverfion of but one meafure ? and yet ic is moft
certain : And this truth meets with fo manifeft proofs ,n experi-
ence, that it is very admirable! And for the full fat.sf|a.on of
thofe who not being able to comprehend fubnl demonftrati-
ons defireto be clearly inform'd by the matters ot taft, and to
fee with their bobily eyes, and touch with their hands, what their
underftandingand reafon cannot reach unto: I will hear *dd
another very eafie way to reduce all to an experiment , tte

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2°K.B. 9,163

Of the l^Ei^suK hr ion

which may be made in little , in great, or in very "great

L ik U
of

which I make ufe frequently, to the admiration ti fuch as lee it-
I prepared an hundred Siphons, or5if you will, bowed Pipes,
all equal ^ and placed them at the brim of a Veficl , wherein the
water is kept at one and the fame level (whether all the Syphons
work, or but a certain number of them) the mouths by which
the water iffueth being all placed in the fame level, parallel to
the Horizon 5 but lower in level than the water in the Veffcl, and
gathered all the water falling from the Syphons into another
VciTel ftanding lower than the former, 1 made it to run away
thorow a Chanel ^ in fuch manner inclined , that wanting water
from the Syphons, the faid Chanel remained quite dry.

And thii) done, 1 meafured the quick height of the Chanel
with care, and afterwards divided it exafily into lo equal parts,
andcaufingip. of thofe Syphons to betaken away,fo that the
Chanel did not run water, Tave onely with 8 1 of thole Syphons,
I again obfcrved the quick height of the water in the famefite
obferved before, and found that its height was ^iiT^inifl^^^ P**^*
cifely the tenth part of all its firft height , and thus continuing to
'take away 17. other Syphons, the height was likewifc diminifli-
ed f. of all its firft quick height j and trying to take away 1 5.
Syphons, then 1 3) then 1 1 , then 9, then 7, then 5, and then 3.
atwaies in thefc diverfions,made in order as hath been faid, there
enfued fiill an abatement of ^. of the whole height.

And here was one thing worthy of obfervation, that the water
cncteafingin \j>r throHgVT^ the Chanel,its quick height was diffe-
rent in different fites of the Chanel, that is ftill leffer , the more
one approached to the Out-let; notwithftanding which the abate-
ment followed in all places proportionably, that is in all its fites
the firft part of the height of that fite diminiflied : And more-
over the water ifTued from the Chanel,and dilated into a broader
courfe, from which likewlfe having divers Out-lets and Mouths;
yet neverthelefs in that breadth alfo the quick heights fucceflive-
ly varied and altered in the fame proportions. Nor did I here
defift my obfervation, but the water being diminiflied, that iffu-
ed from the Syphons, and there being but one of them left that
difcharged water \ 1 obferved the quick height that it made in the
above- faid fites, fthe which was likewife 7. of all the firft height)
there being added to the water of that Syphon, the water of
three other Syphons *, fo that all the water was of 4 Syphons,
and confequently quadruple to the firft Syphon ^ but the quick
height \^s onely double , and adding five Siphons, the quick
height became triple, and with adding ftven Syphons,the height
xncreafed quadruple ; and fo by adding of 9. it increafed quin-
tuple , and by adding of 1 1 , it increafed fcxtuple , and by ad-

ding

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2°K.B. 9,163

r Lib. J. R U 1^ N I N G

ding of 15. itincreafed feptuple, and by adding of 15. oftuple?
and by adding of 1 7. nonuplcjand laftly by adding 19. Syphons j
fo that all the water was centuple to the water of one Syphon?
yet nevertheleCs the quick height of all this water was onely de-
cuple to the firft height conjoyned by the water that iffued froni
one onely Syphon.

For the more clear under/landing of all which, I have made
the following Figure 5 in which we have the mouth A, that
maintaineth the water of the Veffel B C in the fame level j though
it continually run 5 to the brim of the Veffel are put 35. Sy-
phons (and there may be many more) divided into 5 Claffes,
D E F G H, and the firft D, are of one onely Syphon ^ the fecond
E5 of three Syphons j the third F, of five j the fourth G, of 7 , the
fifth H, of 9 i and one may fuppofc the fixth of 1 1, the feventh
of 1 3 Syphons, and fo of the other Claffes, all containing in con-
fequent odd numbers fucccflively (we are content to reprelent in
the Figure no more but the five forcnamed Claffes to avoid con-
fufion) the gathered water D E F G H, which runneth thorow
the Chanel 1 K L, and falleth into the out-let M N O F i and fo
much fuflScethfor the explanation of this otperiment.

Of the Mensuration;

PROPOS. V. PROB. III.

j^ny River ofanybignefs, if being given to examine the
quantity of the Water thn runneth tkorow the Kiver
in a time ajfigned.

BY what we have faid already in the two preceding Pro-
blems, we may alio relolve this that we have now before
us 5 and it is done, by diverting in the firft place from the
great River a good big meafurablc Chanel, as is taught in the
iecond Probleme , and obfervlng the abatement of the River,
caufcd by the diverfion of the Chanel and finding the proporti-
on that the Water of the Chanel hath to that of the River, then
let the Water of the Chanel be meafured by the fccond Pro-
bleme^ and work as above, and you lhall have your defire.

CONSIDERATION. I.

ANd although it feemeth as if it might prove difficult, and
almoft impoffible to make ufe ofthe Regulator number? if
one be about to meafure the water of fome great River,
and confequently would be impoffible, or at leaft very difficult
to reduce the Theory of the firft Probleme into prafticc : Yet ne-
verthelefs, I could fay that fuch great conceits of meafuring the
water of a great River, are not to come into the minds of any
but great Pcrfonages, and potent Princes j of whom it is cxpefted
for their extraordinary concerns, that they will make thefe kinde
of enquiries ^ as if here in Italy it fhould be of the Rivers Tyber^
VelinO'i Chiana^ Arno^ Serchio^ Adice-, in which it feemeth real-
ly difficult to apply the Regulator, to finde exaftly the quick
height of the River: Butbecaufein fuch like cafes fometimes
it would turn to account to be at fome charge, to come to the
iexaft and true knowledge of the quantity of water which that
River carrieth , by knowledge whereof , other greater dif.
burfmcnts might afterwards be avoided, that would oft times be
made in vain; and prevent the difgufts , which fometimes happen
amongft Princes : Upon this ground I think 'it will be well to
fliew alfo the way how to make ufe of the Regulator in thefe
great Rivers j in which if we will but open our eyes, we fhall meet
with good ones , and thofe made without great cofi: or laboui'?
which will ferve our turn.

For upon fuch like Rivers theKe are Wears, or Lockcs made^

A T E R S,

Lik 3. Of Running

to caufe the Waters to rife, and to turn them for the fervice of
Mills, or the like. Now in thefe pafes it is fufficient that one
crca upon the two extreames of the Weare two Piladers either
of Wood or Brick, which with the bottome of the Weare do
eompofe our Regulator, wherewith we may make our defired
operation, yea the Chanel it felt diverted ft,all ferve , without
inaking any other diverfion or union. And in briei , it the bu-
iincffes be but managed by a judicious perfon, there may waycs
and helps be made ufe of, according to occafion, of which «
would be too tedious to fpeak, and therefore this little that hath
hinted (hall fulRcc.

CONSIDERATION II.

FRom what hach been declared , if it (hall be well under-
flood may be deduced many benehts and convemences,
not o'nely in dividing of Running Waters for infinite ufeS
fhat thev are put to in turning of Corne-MiUs, Paper-MiUs,
cZ Powder-Mills, Rice-Mills, Iron- Mills , Oil-Mills , Saw-
L-Mills, Mirtle-MiUs, Felling-MiUs, FuUing-Mills, Silk-Mills,
and fuch other Machines ; but alfo in ordering Navigable Cha-
nels, diverting Rivers and Chapels of Waters or terminating
Ld imiting the fixes of Pipes for Fountains : In all which af-
fairs there .re great crrours coiflaiitted, to the lolTe of much
expence, the Chanelsand Pipes that are made, fometimes not
being fufficient to carry the defigned Water, and fometunes they
arc made bigger than is ncceflfary which ^iforders (haU be
avoided, if the Engineer be advifed of the things f ov^f^'^-
in cafe that to thefe Notions there be added the knowledge of
PhilofophY and Mathematicks, agreeable to the fublime Difco-

vcVs of h»ore GaUUo, and the further improvement thereof
venes oi i / /?, r^.-r/tc/// Mathematician to the Grand

^holc bufini(re'of Motion, one (hall then ^ome to the W
Sae of particular notions of great curiofity m the Theonck ,
and of extraordinary benefit in the Praaicks that daily occur in

^tnd"o"£v, in effea, of what utility thefe Notions are I

havllught fit toinlert, in this place, the Confideranons by

nave tnougni ^ y reprefent,.

me made upon Lake o^/j ' ^ . ^^e m^^

at large, by the -P--^^;/:^ ffid RepW- Being

rreforaTr:J!^t?e7earaforefaiJI^

S lUuft-ious ai^l moft Excellent S.gnore C^.vanm

Of tl/e Mensuration; Lib.2-

donnai^ Scnztouv of great worth and merit, that 1 wCuld inge-
nuoufly deliver my opinion touching the ftate of the Lake
of Venire -^ and after 1 had difcourfcd with his Honour fcve-
ral times , in the end I had order to fet down the whole
bufineffe in writing, who having afterwards read it privately,
the faid Signore imparted the fame, with like privacy, to the
moft Serene Prince, and I received order to reprefent the
fame to the full ColUdge , as accordingly 1 did in the Moneth
of M4y , the fame year , and it was as followcth.

CONS I DERATIONS

Concerning the

LAKE
VENICE

B Y

D. BENEDETTO CASTELLI,
Abbot of S. Benedetto Aloyfio , Mathematician to
Pope VKBA^ Vlll and Profeflbr in
Rome.

COT<iSlDEK ATlOli I

Hough the principal caufc be but one
onely, that in my judgment threatncth
irreparable ruine to the Lake of
Venice^ in the prefent ftate in which it
now ftands ^ Yet nevertheleffe , I think
that two Heads may be confidcred.
And this Confideration may peradven-
t urc ferve us for to facilitate and explain

the opportune remedies, though not to

render the ftate of things abfolutely unchangeable and eternal:,
an enterprize impoffible, and Specially in that which having had
fomc beginning, ought likewile necclTarily to have its end i or
at leaft to prevent the danger for many hundreds of years ; and
poffiblyitmay, in the mean time, by the mutation it fclf be
brought into a better condition.

Hay therefore, that the prefent diforder may be confidercd
under two Heads One is the very notabk difcovery of Land
that is obferved at the time of low Water, the which, befides
the obftruSing of Navigation in the Lake and alfo in the
Chanclsy doth likewif: threaten another mifchief and diford<!^^

wG^irtfty

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2°K.B. 9,163

Of the Mensuration Lib.

worthy of very particular confidcrationr which is. That the Sun
drying up that mudde, efpccially in the times of hoc Summers,
doth raife thence the putrified and pernicious vapours, fogs, and
exhalations that infeft the Air, and may render the City unha-
bitable.

The fecon4 H is the great Stoppage that daily is grow-
ing in the Ports, d|>ecially of Venice^ u Malamoco concerning
which matters I will hint certain general points, and then
will proceed to the more particular and important affairs.

And firftjl fay, that I hold it altogether impoflible to cfFeS:
any thing, though never fo profitable? which doth not bring with
it fome miCchief j and therefore *(be good and the hurt ought to
be very well weighed, and then the lefle harmful part to be im-
braced.

Secondly, 1 propofe to confidcration, that the fo notable dif-
covery of Earth &: Mud, hath not been long oblcrved.as I undcr-
ftand, from old perfons that can remember pafl'ages for fifty
years paft , which thing being true, as to me it feeraeth moft
true, it fliould apppar that it could not but be good to reduce
matters to that paflb that they were at formerly, (laying afidc
all affeftion or paflion that felf- flattering minds have entertained
for their own conceits) or at leaft it fliall be neceffary fpeedi)y to
confult the whole.

Thirdly, I hold that it is necelfary to weigh^whether from the
forefaid difcovcry of Land, it foUowtth, that onely the Earth ri-
feth, a$ k is commonly thought by all, without difpute , or whe-
ther rhc Waters are abated and fain away , or eife whether it
proccedeth from both the one and other caufe. And here it would
be feafonable to enquire, what fliare the faid caufcs may have,
each confidered apart in the forefaid efFeft. For, In the firft
cafe, if the Earth have been raifed, it would be neceffary ta
confider of taking it down, and removing it : But if the Wa-
ters have failed or abated, I believe that it would be extreamly ne-
cefTary to reftore and raife them : And if both thefe reafons have
confpired in this efFeft, it will be necelFary to remedy them each
apart., And I do, for my part, think, that the fo notable appea-
rance of Shelves at the time of low Water, proceeds principally
ftom the decreafe and abatement of the Waters, which may
confidently be affirmed to need no other proof, in regard that the
Bre;2t hath been aSually diverted which did formerly difcharge
its Water into the Lake.

As to the other point of the great Stoppage of Ports, I hold,
that all proceedeth from the violence of the Sea, which being
fometimes difturbed by windes, efpccially at the time of the vi^a-
ters flowing, doth continually raife from its bottome immenfe

heaps

lik-i. 0/ Running Waters.

heaps of find, carrying them by the tidci and force of the waves
n.to the Lake ; it not having on its part any fttength of current
that may raife and carry them away, they fink to the bottom, and
lo they choke up the Ports. And that this elFea happeneth in
this manner, we have moft frequent experiences thereof along the
Sea-coafts : And I have obferved in Tufcany on the Roman-
(};ores, zadm the Kingdom of of N<i/>/e/, that when a river fal-
leth into the Sea,thcre is alwaies feen in the Sea it felf,at the place
of the rivers out-let, the refemblance,as it werc.of an half-Moon,
or a great (helf of fettled fand under water, much higher then the
reft of the (hore, and it is called in Tufcany, il Cavallo ; and here
iaVeniccloScanto : the which cometh to be cut by the current
of the river, one while on the right fide , another while on the
left and fometimes in the midft, according as the Wind fits. And
alike efFec'i I have obferved in certain little RiUets ot water,
along the Lake oi B0lfena->^\t\i no other difFerence,fave that of

fmall and great. , , . a- « i • i r .u u

Now whofo well confidercth this efFea, plainly feeih that it
proceeds from no other , than frofn the contrariety of the ftream
of the River to the tmfetm of the Sca-waves ; feeing that
great abundance of fand which the Sea continually throws upon
thefliore, cometh to be driven into the Sea by the ftream ot the
river i and in that place where thofe two impediments meet
with equal force, the fand fetleth under water, and thereupon »s
made that fame Shelf or Cwvallo-, the which if the river carry
water, and that any confidetable ftorc, it fliall be thereby cut
and broken i one while in one place, and another while in ano-
ther as hath been f.id , according as the Wind blows . And
throuehthat Chanel it is that Vcifels fall down into the S^a, and
again maketo the river , as into a Port. But if th. Water of
the river (hall not be continual or (hall be weak, in that cafe the
Sceofthe Sea-Wind fhall drive fuch a quantity of fand into
E mlhofthePort,andoftheriver,asM^ «
UP And hereupon there are feen along the Sea-fide, very many
Lakes and Mccrs, which at certain times of the year abound wuh
waters, and the Lakes bear down that enclofure , and run into

*^^Now it is nea fl^ry to make the like reHeaions on our Ports
oiVen,ce,mamcco, Bondolo, arid Cfci.x*. i which in a certain
fcnfe arc no other than Creeks, mouths,and openmgs of the fl,jre
that parts the Lake flom the main Sea ; and therefore I hold that
if the Vatcrsin the Lake were plentiful , they WQold have
ftrength to fcowt the mouths of the Ports thqrowly, & with great
force i but the Water in the Lake failing ,, the Sea will with-
out any oppofal, bring fuch adrift o£ M into the Ports i thi»« |

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2°K.B. 9,163

Of the UiEWSMK k-x ion • Lib*

it doth not wholly choke them up, it (hall render them at kaft
unprofitable , and impoffible for Barks and great Vcflcls.

Many other confiderations might be propounded concerning
thefe two heads of the ftoppage of the Ports, and of the appea-
rance of the Ouxe and Mud in the Lakes, but fo much {hall fuf-
fice us to have hinted, to make way for dilcourfing ot the opera-
tions about the oportune remedies.

Yet before that 1 propound my opinion, I fay, That I know
very well that my propofal,at firft fight, will feemabfurd and in-
convenient ^ and therefore, as iiich, will perhaps be rcjefted by
the inoft : andfo much the rather, for that it will prove direftly
contrary to \vhat hath hitherto been,and as I hear, is intended to
be done .* And I am not fo wedded to my opinions , but that I
do confider what others may judge thereof : But be it as it will,
lam obliged to fpeak my thoughts freely, and zhat being done,
-I will leave it to wifer men than my fclfj when they (hail have
well confidered my reafons, to judge and deliberate of the qnid
ttgendnm : And if the fentcnce ftall go againft me,I appeal to the
mofttqt^itable and inexorable* Tribunal of Nature, who not
caringift the leaft topi eafe either one party or another, will be
alwaies a purifttial afid inviolable executrix of her eternal De-
crees , i^inft which neither humane deliberations., nor our vain
defires, fliall ever have power to rebell. I added by word of
mouth that which foUoweth.

Though your Highnefs intereft your felf in this Noble Col-
in Preg4di, a 5tdges^^ic*d ca\rfe it to be co nfirmed in the * Senate by univerfal
pirticular Coun- Votc, that the Wiuds do not blow,that the Sea doth not flufiuate,
thattheRii^ersdonot run 5 yetfliallthe Wmds be alwaies deaf,
thfeSeafhkUbeconftantinitsfnconftancy ,and the Rivers riioft
•obftiriate ; ' And thefe fliall be my Judges, and to their detcrmi-
ti^tkh!ili^(€T «iy felf.

By #hati:1iath be^n faid, in my opinion,that is made very clear
and fnanif eft -which in the beginning of this difcourfe I glanced
at . namely. That the whole diforder, although it be divided into
two heads; into the difcovery of the Mud, and of the ftoppage
MP^^^^^J^etiAeverthekfs, by the application of one onely remedy,
and that in my efteem very eafie, the whole fliall be removed:
Attdthis^it'i^ ^ That ' there be reftored into the Lake as much
Water^s' t^n be poflTiblej ahd in particular from the upper parts
of l^e;/^;^taking ftitef that the Water be as free from Mud as is
'poflible. And that this is the true and real remedy of the prece-
^enft difot-derSj !^ mariifeft ; For in the paflage that this Water
^ll iiifiik^ thoroWth^^ fliall of it felf by degrees cleat

^'^^^'^'^^s iri futtdfy'^arts of them, according to the currents
^tHat ft^lh^RtutieffiN^ri;^ acqui^^^ ^indin this manner being dif-

perfed

cil, the Senators of
Which have great
Authority.

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2°K.B. 9,163

Lib. 2. Of Kunming

pcrfed thorow the Lake, it (hall maintain the waters in the famcj
and in the Chanels much higher, as I fliall prove hereafter ; a
thingthat will make Navigation commodious 5 and that, which
moreover is of great moment in our bufinelTe ; thofe Shelves
of Mud wliich now difcover themfelves at the time of Low-
Waters fliall be alwayes covered, (o that the putrefaftion of
the Air fliall alfo be remedied.

And laftly, this abundance of Water being alwayes to dif-
charge it felf into the Sea by the Ports, I do not doubt, but that
their bottomes will be fcoured. And that thefe cffe&s muft fol-
low, Nature her felf feemcth to perfwade, there remaining onely
one great doubt, whether that abundance of Water that fliall be
brought into the Lake may be really fufficient to make the Wa-
ters rife fo much as to keep the Shelves covered, and to facilitate
Navigation, which ought to beatleaft half a * Brace, or there-
abouts. And indeed it feemeth at firft fight to be impofllble,
that the fole Water of the * Brent let into the Lake, and dif-
perfed over the fame, can occafion fo notable an height of water;
and the more to confirm the difficulties, one might fay, reducing
the reafon to calculation, that in cafe the Breut were 40. Bra-
ces broad, and two and an half high, and the breadth of the
Lake were 20000. Braces, it would fecm neceffary that the
height of the water of the Brent dilated and diftended thorow
the Lake would be but onely -v^ of a Brace in height, which is
imperceptible, and would be of no avail to our purpofe i nay
more, it being very certain that the Brent runneth very muddy
and foul, this would occafion very great mifchief, filhng and
contraaing the Lake, and for that reafon this remedy ought, as
pernicious, to be totally excluded and condemned. .

1 here confeffe that I am furprized at the forme of the Argu-
ment as if I were in a certain manner convinced, that I dare not
adveinuretofaymorc, or open my month in this matter-, but
the ftrenath it felf of the Argument, as being foiinded upon
the means of Geometrical and Arithmetical Calculation, hath
opened me the way to difcover a very crafty fraud that is couch-
ed in the fame Argument, which fraud 1 wdl make out to any
one that hath but any infight in Geometry zui ArtthmcticL
And as it is impofllble, that fuch an argument fcpuld be produced
by any but fuch as have tafted of thefe, in fuch affairs, inoft pro-
fitable, and moft neceffary Sciences ^ fo do not 1 pretend to inake
invfelfunderftood, fave onely by Inch, to whom 1 will evince,
fo clearly, as that more it cannot be defired, the errour and fraud
wherein thofe Ancients and Moderns have been, and alwayes
are intangied, that have in any way yet handled this matter of
confidering the Meafure and Qpantity of the Waters th^ njoy^i

Kkkk a Ana

is ^ of our yard,

• A Rircr of
that name.

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2°K.B. 9,163

Of the Mensuration

n I, Savii dell*
!if^^/r*j a particu-
lar Council that
take care of the
Lakes anH other
Aquatick af&irs.

And fo great is the efteeir that I have for that which I am now
about to fay touching this particular, that I am content that all
the reft of my Difcourfe be rejefted ^ provided, that that be per-
feSly underftood, which lam hereafter topropofe, I holding
and knowing it to be amain Principle, upon which all that is
founded that can be laid either well or handfomcly on this parti-
cular. The other Difcourfes may have an appearance of being
probable, but this hits the mark as full as can be delired, arriving
at the higheft decree of certainty.

I have, feventecn years fince, as I reprefented to the moft Se-
rene Prince, and to the Right Honourable the Prcfident of the
Lords the Commifltoncrs of the *Sewers,written a Treatiie of the
Meafure of the waters that move, in which I Geometrically de-
monftrate and declare this bufinefle, and they who (hall have
well underftood the ground of my DifCourfe, will reft fully fa-
tisfied with that which I am now about topropole : But that all
may become rhe more eafie, I will more briefly explicate and
declaie fo much thereof as I have demonftrated in rhe Difcourfe,
which will fuffice for our purpofe : And if that fliould not be
enough, we have alwayes the expenment of a very eafie and
cheap way to clear up the whole bufinefTe. And moreover I
will take theboldnefle to affirm, that in cafe there ftould not for
the prefent any deliberation be made concerning this affair, ac-
cording to my opinion ^ yet ncvertheleffe it will be, at fome
time or other ^ or if it be not, things will grow worfe and
worfe.

For more clear underftanding, therefore, it ought to be known,
that it being required, as it is generally ufed, to meafure the wa-
ters of a River, its breadth and its depth is taken, and thefe two
dimenfions being multiplied together, the produft is affirmed to
be the quantity of that River : As for example, if a River (hall
be lOO. feet broad, and 20. feet high, it will be faid, that that
River is tiooo feet of Water , and fo if a Ditch (hall be 1 5 . feet
broad, and 5. feet high, this fame Ditch will be affirmed to be
75. feet of Water : And this manner of meafuring Running
Water hath been ufed by the Ancients, and by Moderns, with
no other difference, fave onely that fome have made ufe of the
Foot, others of the Palme, others of the Brace, and others of
oth^r tneafurcs.

Now becaufe that in obferving thefe Waters that move, I fre-
quently found, that the fame Water of the fame River was in
fome (ites of its Chanel pretty big, and in others much leffe,
tiot arriving in fome places to the twentieth, nor to the hundreth
P*tt of that which it is feento be in other places ; therefore this
vulgar Sway of meafuring the Waters that* move, for that they did

not

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2°K.B. 9,163

Lib.^. 0/" Running Waters.

not give me a certain and liable meafure and quantity of Water?
began dcfcrvedly to be fufpefted by me, as difficult and defcflive^
being alwayes various, and the meafure, on the contrary, being
to be alv^ayes determinate, and the fame , it is therefore written,
thAt Pondfis ^ Fondfis^ Menfnra ^ Menfnra^ utruntque abomi-'
nabile eji apud Denm^ Exod. I confidercd that in the Terri-
tory of Brefcia^ my native Gountrey, and in other places, where
Waters are divided to overflow the Grounds, by the like way of
meafuring them, there were committed grievous and moft impor-
tant errours, to the great prejudice of the Publique and of Pri-
vate perfonsj neither they that fell, nor they that buy under-
ftanding the true quantity of that which is fold and bought : In
regard that the fame fquare meafure, as is accuftomed in thofe
parts, affigned one- particular perfon, carried to fometimes above
tvvice or thrice as much water, as did the fame fquare meafure af-
figned to another. Which thing proveth to be the fame incon-
venience, as if the mealurc wherewith Wine and Oil is bought
and fold, fliould hold twice or thrice as much Wine or Oil at one
time as at another. Now this Confideration invited my mindc
andcuriofity to the finding out of the true meafure of Running
Waters. And in the end, by occafion of a moft important bu-
fineffe that I was imployed in fomc years fince, with great in-
tenfeneffc of minde, and with the fure direSion of Geometry , I
have difcovered the miftake, which was, that we being upon the
bufineffc of taking the meafure of the Waters that move,do make
ufe of two dimenfions oncly, namely, breadth and depth, keep-
ing no account of the length. And yet the Water benig, thoagh
running, a Body, it isneceffary in forming a conceit of its quan-
tity, in relation to another, to keep account of all the three Di-
menfions, that is of length, breadth, and depth.

Here an objeftion hath been put to me, in behalf of the ordi-
nary way of meafuring Running Waters, in oppofition to what
I have above confidered and propofed : and 1 was told, lis true,
that in meafuring a Body that ftands ftill, one ought to take all
the three Dimenfions , but in meafuring a Body that continually
moveth, as the Water, the cafe is not the fame : For the lengih
IS not to be had, the length of the water that moveth being infi^
nite, as never finifliing its running ^ and confequcntly is incom-
prehenfible by humane underftanding,and therefore with reafon,
nay upon neceflity it cometh to be omitted.

In anfwcr to this, I fay, that in the abovcfaid Difcourfe, two
things are to be confidered diftinftly j Firft, whether it be poffible
to frame any conceit of the quantity of the Body of the Water
with two Dimenfions onely. Andfecondly, whether this leng^^
be to be found . As to the firft, I am very certain that no mafl,ict

hint

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2°K.B. 9,163

Of the M E N S U R A T I 0 Ni' Lih.t^

him be never fo great a Wit, can never promife to frame a con-
ceit of the quantity of the Body of Water, vrithoa't the third
Dimenfion of length : and hereupon I return to affirm , that the
vulgar Rule of meafuring Running water is vain and erroneous.
This point being agreed on, I cbme to the fccond, which is, Whe-
ther the third Dimenfion of length may be meafured. And I fay,
that if one v^ould know the whole length of the water of a
Fountain or River, thereby to come to know the quantity of all
the Water, it would prove an impoffible entcrprize , nay the
kaowing of it would not be ufeful. But if one Would know how
much water a Fountain, or a River carricth in a determinate tinle
of an hour, of a day, or of a moneth, &c. I fay, that it is a very
pofllble and profitable enquiry, by reafon of the innumerable
benefits that may be derived thence, it much importing to know
how much Water a Chanel carrieth in a rime given and I have
demonftrated the fame above in the beginning of this Book and
of this we ftand in need in the bufineffe of the Lake, that fo we
may be able to determine how muchfliall be the height of the
Brem^ when it is fpread all over the Lake : For the three dimen-
fions of a Body being given, the Body is known ; and the quan-
tity of a Body being given, if you have but two dimenfions, the
third fliall be known. And thus diving farther and farther into
this Confideration, I found that the Velocity of the courle of the
water may be an hundred times greater or leffcr in one part of
its Chanel than in another. And therefore akhough there (hould
be two mouths of Waters equalin bigneffe yet nevcrtheleis it
might come to paffe, that one might difcharge an hundred or a
thoufand times more water than another : and this would be, if
the water in one of the mouths fliould run with an hundred or a
thoufand times greater velocity , than the other for that it
would be the fame as to fay, that the fwifter was an hundred or
^thoufand times longer, than the flower : and in this manner I
difcovered that to keep account of the velocity, was the keeping
account of the Length.

And therefore it ismanifeft, that when two Mouths difcharge
the (ame quantity of Water in an equal velocity, it is neceffary
that the lefs fwift Mouth be fo much bigger than the more fwiftj
as the more fvvift exceedeth in velocity the lefs fwift v as fot
example.

In cafe two Rivers fliould carry equal quantity ot water irt

equal times, but that one of them fliould be four times more

fwift than the other, the more flow fliould of neceflity be four

times more large. And becaufe the fame River in any part

thereof alwaiesdifchargeth the fame quantity of Water in equaf

times <;as k demonftrated in the firft Propofition of the (trn

Book:

Lih.^l 0/ R unning Waters. 71

Book* of the nieafiire of Running Waters *,) but yet doth not th^'oemonftrnt

run thorowout with the fame velocity : Hence it is, that the vul- following, at

gar mealuresofthelaid River,in divers parts of its Chanel, are 2001""^°^'^'^'^

alwaies divers j infomuch, that if a River paQing through its cha-

nel had fuch velocity, that it ran i oo Braces in the 1° of an hour-

and afterwards the fa id River (hould be reduced to fo much tardi,

ty of motion, as that in the fame time it (hould not run more than

one Brace, it would be neceflary that that fame River fliould be-

con]e ICQ. times bigger in that place where it was retarded ; I

mean, loo. times bigger than it was in the place where it was

fwifter. And let it be kept well in mind, that this point rightly

underftood, will clear the undei ftanding to difcover very many

accidents worthy to be known. But for this time let it fofficei

that we have onely declared that which makes for our purpofe,

referring apprehenlivc and ftudious Wits to the perulal of my

aforenamed Treatife \ for therein he fliall finde prorit and delight

both together. -

Now applying all to our principal intent, T fay; That h^y^hat
hath been declared it is manifeft, that if the Br^m were 40/ Bra-
ces broad, and a! high, in forae one part of its Chanel, that after-
wards the fame Water of the Brm falling into j:^e Lake, arid][^af-
{Jngthorow the fame to the Sea, it fhou Id lofe'io much of it^ ve-
locity , that it ihould tuii but one Brace, in the time whiei^ta
whilft it was in its Chanel atthe^hce aforefaid, it ran loo.'Bra-
ccs. It would be abfolutely neceffary , that increafing in mea-
fure,it flhould become an hundred times * thicker and therefore *Dccp«c
if we ihould fuppofe that the Lake were aoooo. BrA«ea ^ <be
Brf^'^ that already hath b^dtirn fiTpporR'^ in its Chanel 160. B^ces,
treing brought into tlie^Lake, flioaW be 100. times loo.Bratesi
thatis (hall be loood ^Bratcs in-thhiknefs, and confequehtly fliall
..be in height half a Brace V thitls • -^^^df a Bra'de, and hotV^ oi z
B't^ce, aV was concluded in the A?gt^^^ / * i

' Now oiVe may fee iptoSvhat a ^roft errour of 99. in 100. one
m^y fall through the ttbt%dl uhdei'ftanding ^li^ true ^hanthy

RunningWater, whteh'being \i^cll and WftooU , doth op^en a
tlirfea way to pur )udgir<g'ari^ht in 'this moft cbrifiderabl6^^l¥air.
^ i>And theretore adrilutiiig that WciH Mtb^^^ dtmorrfti^ited,
"IT^y, thati . would (if it did co'rtCern iWe) gifWtl|^^'eticline to con-
fiih upon the' returning of'tVj^^^ ^b'aih ihW:ft For it

being moft evident, that the Brih\ iii'irtie' CKA'iitl of its moui*> is
much fwifter than the Brent being brought into the Lake , it will
certainly follow thereupon ,that the thtcknefy of the Water of
Brent in the Lake, fliall be fo much greacer than t.iat of Brent in
Bre^^, by how much the Bront mBrent is fwifter thaa thh Brent
in the Lake,

f, from

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2°K.B. 9,163

Ofibe MeNSU RATIOS Lib,t;

1. From which operation doth follow in the fir'ft place, that
the Lake being filled and increafed by tbcfe Waters , (hall be
more Navigable, and paflible, than at prcicnt we fee it to be.

2. By the current of thefe Waters, the Chancis will be fcoiu-
•ed, and will be kept clean from time to time.

3. There will not appear at the times ct low- waters fo many
Shelves, and fuch heaps of Mud, as do now appear.

4. The Ayr will become more wholcfom, for that it (hall not
be fo infefted by putrid vapours exhaled by the Sun, fo long as
the Miery Ouze fliall be covered by the Waters.

5. Laftly, in the current of thefe advantagious Waters„which
muft iffue out afthe Lake into the Seajbefides thofe of the Tyde,
the Ports will be kept fcoured, and clear : And this is as much as
I (hall offer for the prefent, touching this weighty buifinefs ; al-
waies fubmitting my felf to founder judgements.

Of the above-faid Writing I prefented a Copy at Venice^ at a
full Colledge , in which I read it all, and it was hearkned to with
very great attention j and at laft I prefented it to the Duke, and
left fome Copies thereoif with fundry Senators, and went my way,
promifing with jal intenfenefs to apply my pains with reiterated
ftudies in the publick fervice i and if any other things fliould come
into my mindc, I promifed to declare them fincerely , and fo took
leave o( His fere nttj^ 2Lnd that Noble Council. When I was
returned to Rowc, this bufincfs night and day continually run-
ning in my mind^ 1 hapncd to think of another admirable and
moft important conceit, which with efFe6iual rcafons , confirmed
by cxaft opcrationSj I with the Divine alfiftance , made clear and
manifcft ^ and i hough the thing at firft fight feemed to me a moft
extravagant Paradox, yetnotwithftanding , having fatisfiedmy
felf of the whole bufincfs, I fent it in writing to the moft Illuftri-
ous and moft Noble S ignore Gio, Bafadoma 'j who after he had
well confidered my Paper, carried it to the Council , and after
that thofe Lords had for many months maturely confidered
thereon, they in the end refolved to fufpend the execution of the
diverfion which they had before confultcd to make of the River
and of four other Rivers, which alfo fall into the Lake; a
thing by me blamed in this fecond Paper, ^^^^ prejudicial^
and harmful. The writing fpake as followetb.

Lib.7.

CONSIDERATION S

Concerning the

LAKE
VENICE

C Oti SIDERATION I L

the difcourfing well about the truth of
things, Moft Serene Prince, were as the
carrying of Burdens, in which we fee
that an hundred Horfes carry a greater
weight than one Horfe onely i it would
fcem that one might make more account
of the opinion of many men^'t^ian of
one alone^ But beeaufe that difcourfing
more refembleth running, than carrying
Burdens, in which we fee that one Barb alone runneth fafter
than an hundred heavy-ht^el'd Jades^ therefore I have evermore
efteemed one Conclufion well managed, and well confidered by
one underftanding man, although alone, than the common and
Vulgar opinions^ efpecially, when they concern abftruce and
arduous points: Nay infuch cafes the opinions moulded apd
framed by the moft ignorant and ftupid Vulgar, have been ever
fufpefted by measfalfe, for that it would be a great wonder if
in difficult matters a common capacity fliould hit upcin that
which is handfom , good, and true. Hence I have, and do hold
In very great veneration the fumme of the Government of the
moft Serene, and eternal Rep.ublick of Venice-^ which although,,
as being in nature a Common-wealth, it ought to be governed by
the greater part j yet neverthelefs, in arduous affairs, it^ is alwaies
difefted by the Grave Judgement of few,and not judged bUhdJy;

LllI ^

Of the Men s u r a t i o n L//^. 2-

by the Plebeian Rout. Tis true, that he that propoundcth Prd-
|)ofitions fir above the reach of cominon capacity, runneth a
great hazard ofbcing very often condtmntcl without further Pro-
cefs, or knowledge of the Caufe, but yet for all that, the truth
is not to be deferred in moft weighty affairs, but ought rather to
be explained in due place and time with all pofiiblc perfpicuity ,
that fo being wefl underftood, and conlidered, it may come after-
wards for the CfH^nmon good to be embraced.

This which l%ak in general, hath often been my fortune in
very many particulars , not onely when I have kept within the
bounds of mecr fpeculation, but alfo when 1 have chanced to de-
fcendto Prafiice, and to Operations : and your Highncfs know-
eth very well what befel me the laft Summer 1 641 . when in obe-
dience to your Soveraign Commandjl did in full Collcdge repre-
fent my thoughts touching the ftate of the Lake of Vetuce for
there not being fuch wanting, who without fo much as vouch-
fafing to underftand me, but having onely had an inlding , and
bad apprehenfion of my opinion, fell furioufly upon me, and by
violent means both with the Pen and Prefs, full of Gall, did abuie
me in reward of the .readinefs that I had expreft to obey and
ferve them : But I was above meafure encouraged and pleafed, to
fee that thofe few who vouchfafed to hear me, were all either
thorowly perfwaded that my opinion was well grounded , or at
Icaft fufpended their prudent verdift to more mature deliberati-
on. And though at the firft bout 1 chanced to propofe a thing
that was totally contrary to the moft received and antiquated
opinion j and to the refolutions and confultations taken above an
hundred years ago : Moved by thefe things , and to fatisfie alfo
to the promife that 1 bad made of tendering unto them what
ftiould farther offer it felf unto me touching the fame bufinefs , I
have refolved to prefent to the Throne of your Highnefs, another
Confideritionof no lefs importance, which perhaps at firft fight
will appear a ftranger Paradox , but yet brought to the Teft and
Touch-ftone of experience, it (hall prove moft clear and evident.
If it fljall be accounted of, fo that it fucccedeth to the benefit of
your Highnefs, I fliallhave obtained my dcfire and intent : And
if not, I (hall have fatisfied my felf, and (hall not have been
wanting to the Obligation of your moft faithful Servant, and na-
tive fubjeft.

That which I propounded in the Mouths pafs , touching the
tnoft important bufinefs of the Lake, though it did onely expref-
ly concern the point of the diverfion of the Mouth of the Lake,
already made and put in execution , yet it may be underftood
and applyed alfo to the diverfion under debate, to be made of
the oiVv^r Kve Rivers, and of the Silc in particular.

Mow

Lih.z. 0/RuNNiNG Waters.

Now touching this, I had the fortune to offer admirable
accident that we meet with when we come to the effefi:, which
1 veiily believe will be an utter ruine to the Lake of Ve-

nice.

1 fay therefore, that by diverting thefe five Rivers, that re«
main although their vvater that they difchargefor the prefent in-
to the Lake is not all taken together " parts of what the Brent
alone did carry, yet ncvertheleire the abatement^ of the water of
the Lake which lliall enfue upon this laft diverfion of four parts^
which was the whole water, fliall prove double tb that which ftath
happened by the diverfion of Brent onely, although that the
Brent alone carried five parts of that water, of which the Rivers
that are to be diverted carry four : A wonder really great, and
altogether unlikely ; for the redudngall this Propofition to be
unde'^rftood, is a^ if we fliould fay, that there being given us
three Rivers, of which the firft difchargcth five parts, the fecand
three? and the third one, and that from the diverfion of the
firft there did follow fuch a certain abatement or fall 5 from
the taking away of the fecond there ought to follow alfo fo
much more abatement And laftly , from the withdrawing of
the third the water ought to fall fo much morc,.which is wholly
impoflible ; And yet it is moft certain, and befides the demon-
ftration that perfwades me to it, which I fhall explain in due
time, 1 can fee before your eyes fuch an experiment as is not to
be denied by any one, atlthough obftinate : and I will make it
plainly feen and felt, that by taking away only four parts of the
rive, which fliall have been taken aWay, the abatement pr6vcth
double to the abatement enfuing upon the diverting firft of the
fivconely^ which thing being nue, as moft certainly it isj rt
will give us to underftand how pernicious this diverfion of five
Rivers is like to prove, if ic .fliall be put in executiph.

By this little that lhave hinted , and the much that I could
fay, let your Highneflb gather with what circumfpcaion this bur
finefle ought to be managed, and with how great skill he.orughr .
to be furniflied who would behave himfelf vyell in thefe difficuk

^^I have not at this time, explained the denwnftration, liof kav^
1 fo much as propounded die way to.make the Experiment , that
I am able to make in confirmation of what I have faid, that fp
by feme one or others mif-apprehending the Demonftration,
and maiming the Experiment, the truth may not happen tQ ftine
with lefl'e clarity than it doth, when all mifts of diffic^lty are re-
inoved ; and if fo be, no account fliQuld be made of the Reafons
by me alledged, and that men (hould (hut tl^ir eyes againft the
£xDerimentsthatwitlibut coftoi^!charge.may be made, I do de-
^ LIU a ^latc

MeNSUR A T ION Likt.

clarc send proteft that there (hall follow very great damtnages
to the Fields of the main Land, and extraordinary fummes
(hall be expended to no purpofe. The Lake undoubtedly will
become almoft dry, and will prove impaffible for Navigation,
with a manifeft danger of corrupting the Air : And in the laft
place thcr^ will unavoidably enfue the choaking and ftoppage of
the Ports of Venice.

Upon the aoth.of December^ 1 641 . 1 imparted this my fecond
Confideration to the moft Excellent Signorc Bafadoma^ prefen-
tinghim with a (iopy thereof amongft other Writings, which I
have thought good to infert, although they feem not to belong
dkreftly to our bufineffe of the Lake.

Irtie way to examine the Mud and Sand
that, efttfireth and remaineth in the
Lake of VENICE,

to the mofl Excellent
SiGi^okE GIO. BASADONNA.

TWo very confiderable Objeftions have been made a-
gainft my opinion concerning the Lake of Venice : One
was that, of which I have fpoken at large in my firft
Confideration, tiamely, that the Brents having been taken out of
the Lakci cannot have been the occalion of the notable fall of
the Waters in the Lake, as I pretend, and confequently , that
the iUi-ning Brent into the Lake Would be no confiderable reme-
dy, in regard that the water of Brent^ and the great expanfion
of the Lake over which the water of Brent is to difFufe and
read being coilfidered , it is found that the rife proveth in-
fenfible.

The fecond Objedion was, that the Brent is very muddy , and
therefore if it fliould fall muddy into the Lake, the Sand would
fink and fill up the fame.

_ touching the firft Qiicry, enough hath been faid in my firft
^ntedieratioii, where I have plainly difcovered the deeeipt of the
Argutti^|.^ and fliewn its fallacy , It rcmarnerh now to cxainme

the

Lib, 0/ R U N ^ I k G W A T E R S.

theiccond : to which in the lirft place I fay, that one of thefirft
things that I propofcd in this affair was, that I held it impoffiblc
to do any aft, though never fo beneficial, that was not alfo ac-
companied by fome inconvenience and mifchiefj and therefore
we are to confidcr well the profit, and the loffe and prejudice,
and they both being weighed, we (hall be able to choole the lef-
kr evil: Secondly, 1 admit it to be moll true, that Brent is at fome
times muddy, but it is alfo true, that for the greater part of the
year it is not muddy. ' Thirdly, I do not fee nor underftand
what ftrength this objeflion hath, being taken fo at large, and in
general h and mcthinks that it is not enough to fay, that the
Brent runneth muddy, and to zScn that it depofech its Muddi-
iicffc in the Lake, but we ought ihoreover to proceed to particu-
lars, and ftiew how much this Mud is, and in what time this
choaking up of the Ports may be efFefied. For the Reafons are
but too apparent and particular , that conclude the ruine of the
Lakej and that in a very ftiort time, (for mention is made of
dayes) the Waters diverfion being made, and moreover we
have thccircamftance of ain Experiment, the ftate of things be-
in<' obferved to have grown worfe fince the faid diverfion. And
1 have demonftrated, that in cafe the Diverfion of the Sik and
the other Rivers fliould be put in execution, the Lake would in a
jfcw dayes become almoft dry ^ and the Ports would be loft, with
other mifchievous confequences. But on the other fi<fe, al-
thou£^hth2it we did grant the choaking of them, we may very
probably fay, that it will not happen, fave oiiely in the fucceffion
of many and many Centuries of years. Nor can I tliink it pru-
dent counfel to take a rcfolutton and imbrace a Defigne now, to
obtain a benefit very uncertain, and more than that, which only
fliall concern thofc who are to come very many Ages after us,
and thereby bring a certain inconvenience upon our felves, and
upon our children that are now alive and prefent.

Let it be alledged therefore, (although I hold it falfe) that by
the divcrfions of the Rivers the Lake may be kept in good con-
dition for leveral years to come.

But I fay confidently, and hope to demonftrate it j Thai: the
Oiverfions will bring the Lake, even in our dayes, to be almoft
;3ry, and at leaft will leave fo little water in it, that it fliall ceafe
to be Navi^^able, and the Ports (ball moft infallibly be choaked'
up. I will therefore lay upon experience, in anfwer to this Ob-
leftion, that it is very ncCclTary firft well to difcourfe, and ratio-
nally lo partkularize and aicertain the beft that may be this
point of the quantity of this finking Mud or Sand.

>iow I fear I fliall make my felf ridiculous to thofc, who mea-
faring the thitigs of Nature with the fliallowncffe of their b»Ht»

Off/;e M'E N S U R A T I O N Lib,

do think that it is abfolutely impoffible to make this enquiry, and
will fay unto mQ^Qjiis menfu^ eflfngillo aquai^ i^terram palmo
fonderamt ? Yet ueverthelefs I will propound a way whereby,
at leaft in groftj, one may find out the lame.

Take a Veflel of Cylindrical Figure, holding two barrels of
water, or thereabouts ^ and then fill it with the water of Brent^
at its Mouth OT Fall into the Lake j but in the Lake at the time
that the ^rent runneth muddy, and after it hath be jun to run
muddy for eight or ten hours, to give the itiud time to go as far
as S. !sicolo^ to iffue into the Sea , and at the fame time take
another Vcffel, like, and equal to the firft, and fill it with the wa-
tei of the Lake towards S. Nicolo^ (but take notice that this opc^
ration ought to be made at the tinje when the waters go out^
and when the Sea is calm) and then, when the waters fliall have
fetled in the aforefaid Veffels, take out the clear water, and con-
fider the quantity of Sand that remains behind, and let it be fci:
down, or kept in mind ; And I am eafily induced to think, th^%
thatfliallbe a greater quantity of Sand which fliall be left in the
firft VefTel, than that left in the fecond Veflel. Afterwards
when the Brent lhall come to be clcar,let both the operation^ be
repeated, andobferve the quantity of Sand in the aforefaid Vcf»
(els ^ for if the Sand in the firft Veflel ftiould be moft , it woul4
be a fign, that in the revolution of a year the hrent would dcppfe
Sand in the Lake : And in this manner one may calculate to ^
fmall matter what proportion the Sand that entreth into the Lake,
hath to that which remains : And by that proportion one may
judge how expedient it (hall be for publick benefit. And if at
leveral times of the year you carefully repeat the fame operatic
ons, or rather obfeivations , you would come to a more exa^
knowledge in this bufinefs : And it would be good to make tlje
faid operations at thofe times , when the Lake is difturbed hy
ftrong high Winds, and made muddy by its own Mud, raifed by
the commotion of the Waters*

This notion would give us great light, if the fame obfcrvatiojps
fhould be made towards the Mouth oiLio^ atfuch time as the
waters flow and ebb, in calm feafons j for fo one fliould come to
know whether the waters of the Lake are more thick at the going
out, than at the entrance. I have propounded the foregoing
way of meafuring Sands and Mud, to fliew that we are npt fp
generally, and inconfiderately to pronounce any fentencc, but
proceed to ftrifter inquiries , and then deliberate what lhall be
moft expedient to be done. Others may propofe more exqu?^
fite examinations, but this Oiallferve me for the prefent.

1 Will add onely,that if any one had greater curiofity (it woul4
l^epro&taMe to have it) in inveftigating more exaftly the ^uan^

tib.7. 0/ Waters;

thy of the Water that cntcrcth into the Lake, by the means that
I have fliewen in the beginning of this Book ; When he fhall
have found the proportion of the quantity of water to the quan-
tity of Sand or Mud^ he lhall come to know how much Sand the
Brent (hall leave in the Lake in the fpace of a year. But to
|)erforni thefe things , there are required perfons of difcretion^and
fidelity , and that are imployed by publick Order 5 for there
would thence refult eminent benefit and profit.

Here are wanting L E T T E R S from fevetal perfons.

To the Reverend Father, Francefio dt
S.. Giuseppe.

IN execution of the command that you laid upon me in yem:
former Letters , by order from the moft Serene , my Lord,
Frincc Leopold ^ that I fliould fpeak my judgement conccrn-
int^ the dif imboguement of the River called Fiume morto , whe-
ther it ought to be letintotheSea, or into^^rffcii? 5 I fay, that
I chanced 1 8. years fince to be prefent, when the faid Mouth was
opened into the Sea, and that oiSerchio ftopt j which work was
done to remedy the great Innundation that was made in all that
Country, and Plain oiPtfa^ that lyeth between the River AmQ^
and the Mountains of 5. Ginliano^ and the River Ser^kia which
Plain continued long under water, infomuch that not onely in the
Winter, but alio for a great part of the Summer , thofe fields
were overflowed 5 and when that the Mouth of Fi««r^ morto was
cfFeftuall y opened into the Sea,the place was prefently freed froipi
the waters, and drained, to the great fatisfaftion of the Owners
of thofe Grounds. And here 1 judge it worth your notice, th^t
for^the generality of thofe that poflefs eftates in thofe parts,they
dcovied that the Mouth of Fittme ntorto might fiand open to the
Se»^ and thole who would have it open into Serchio , are perfpm
diat have no other concernment there, fave the hopes of gaining
by having the dilpofe of Commiflicms, and the like, &Cj

But for the more plain underftanding of that which is to be
faidj it muft be known, That the refolution of opening the faid
Mouth into Serchio^ was taken in the time of the Great Puke:
Ferdinando the firft, upon the fame motives that are at this timte
again propofed, as your Letters tell me, Since that, it manifeft-
ly appearing, that Fmme morto had , and hath its Mouth open tp
the Sea, the Plain hathbecn kept dry s and it beii^alfo li\xs^j^4t

Of the MensuraYign; Lib.x

the fury of the South, and South-Weft-VVinds.carr)ed fuch
abundance of fand into the Mouth, or Out-let of Finma money
thatit wholly ftopt it up : efpecially when the waters on fifa
fide were low and (hallow, And they think, that rurning the
\_,2k.t oi Finmc morto 'mtoSerchio^ and the Serchio maintaining
continually its own Mouth with the force of its waters open to the
Sea, andconfequently alio Fiume worto^thcy would have had the
Out-let clear and open ^ and in this manner they think, that the
Plain o(Pifa would have been freed from the waters. The bu-
finefspaffethfor current, at firft fight j but experience proveth
the contrary, and Reafon confirmcth the fame : For the height
of the water of thofe Plains, was regulated by the height of the
waters in the Mouth of Finme morto ^ that is, The waters at the
Mouth being high, the waters aUo do rife in the fields ^and when
the waters at the Mouth are low, the waters of the fields do like-
wife abate: Nor is it enough to fay. That the Out-let or Vent
ofF/«w^wt?r/<? is continual, but it muft be very low: Now if
Finme mno did determine in Serchio ^ it is manifeft that k
would determine high for Serchio terminating in the Sea , whcii
ever it more and more aboundeth with water, and rifeth, it is ne-
ceflary that alfo Finme morto hath its level higher, and confe-
quently (hall keep the waters in the Plains higher. Nay , it hath
happened fometimes (and I fpeak it upon my own fight) that
Fiumemortoh^ith reverfed its courfe upwards towards Pifai
which cafe will ever happen, whenfoever the Pifan waters chance
to be lower than the level of thofc of Serchio ^ for in that Cafe
the waters of return back upon the Plains thorow F^Hm

morto in fuch fort, that the MuddinefTes , and the Serchio have
been obferved to be carried by this return as farr as the Walli of
pifa s and then before fuch time as fo great waters can be aft
fwaged, vvhich come in with great fury, and go out by little and
little, there do pals very many days, and monethsj nay fome-
times'one being never able to find the waters of Serchio,
when at the flialloweft, fo low as the Sea in level j (which ii the
loweft place of the waters) it thence doth follow, that the
ters o{ Finme morto fliould never at any time of the year, fo£^g
as they determine in Serchio, befo low,as they come to be wbetl
the fame Fiume morto determineth in the Sea. Tis true indeed,
that the Mouth of Finme morto^opcned into the Sea, is fub;eft to
the inconvenience of being ftopt up by the force of Winds ; But
in this cafe,it is ncccflary to take fome pains in opening it i which
may eafily be done, by cutting that Sand a little which ftayeth
in the Mouth, after that the Wind is laid j and it is enough if yotf
fl^'^ke a Trench Uttle more than two Palms in breadth j for the
water onct beginning to run into it, it will in a few hours ^^^ff

0/ Running WAters.

that Sand away with it, and there will enfue a deep and broad
Trench that will drain away all the water of the Plains in very lit-
tle time. And I have found by prafiicc, that there having been
a great quantity of Sand driven back, by the fury of the South-
Weft- Wind, into the Mouth of F/w;;/e morto^ I having caufed the
little gutter to be made in the Morning, foniewhat before Noon,
a Mouth hath been opened of 40. Braces wide, and notably deep,
infomuch that the water, which before had incommoded all the
Champian i*anaway in lefs than three dayeg,and left the Coun-
try free and dry , to the admiration of all men. There was pre-
fent upon the place, at this bufinefs , 4| the fame day tha.t I
opened the Mouth, the moft Serene great Duke, the moft Serene
Arch-Dutchefs Mother, all the Commiffioners of Sewers, with
inany other Perfons and Peafants of thofe parts *, and they all faw
very well,that it was never poflible that a little Bark of eight
Oars , which was come from Legorn to wait upon the great
Duke, fliould ever be able to mafter the Current, and to make
up into Fiume morto ; and his Highnefs, who came with an ijitent
to caufe the faid Mouth towards the Sea to be ftopt ^ and that
intoSerf/?/f? to be opened, changed his judgement, giving order
that it (hould be left open towards the Sea, as it was don^e. And
if at this day it fliall return into Serchio^ I am very certain ^at it
will be necefTary to open it again into the Sea. And there vvas
alfo charge and order given to a perfon appointed for the pur-
pole, that he lliould take care to open the faid Mouth , as hath
been faid upon occafion. And thus things have fucceedcd very
well unto this very time. But from the middle of Oi?^^, until
this firft of F^^rw^rj, there having continued high South , and
South-Weft- Winds, with frequent and abundant Rains i it is no
wonder that fome innundatioa hath happened i but yet I will
affirm , that greater mifchiefs would have followed, if the Mouth
had been opened into Serchio. This which I have hitherto faid,
is very clear and intelligible to all fuch as have but competent in-
fight, and indifferent skill in thefe affairs. But that which I an^
now about to propofe farther, will, I am very certain, be under*
ftood by your felf, but it will feem ftrange and unlikely to many
others. The point is, that I fay, That by raifing the level of
FiHfue morto, one half Brace, onely at its Moutt, (it will peni-
penitrate into Serchio farther than it would into the Sea) it (hall
caufe the waters to rife three , or perhaps more Braces upon the
fields towards Fifa, and ftill more by degrees as they fliall recede
farther from the Sea-fide^ and tlius there will follow very great
Innundations, and confiderable mifchiefs. And to know that
this is true, you are to take notice of an accident , which I give,
warning of in my difcourfe of the Meafure of Running Wajce/^ =:
Mm mm wferc

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

Of the MEKiVi KM vo^ Lih. i

V\faeie alio 1 give the reafon thereof, " Coroll. 14. The ac-
cidciuis this, That there coming a Lai d Flocd, for ekampkj
into Arno^ which maketh it to rife above its oidir.ary Mouth
w thin P»/4,or a little above or below the City fix or ieven Bra-
ces ; this lame height becometh alwaics lefllr and leffcr, the ihorc
we approach towards the Sea- fide ; infomuch , that near to the
Sea the faid River {hall be raifcd hardly half a Brace : Whence
itfollowethofneceflaryconfeqiicnce, that fliould I again be ac
the Sea-fide, and knowing nothing of what hapneth, fliould fee
the River Arno raifed by the acceflion of a Land-flood, one third
of a Brace ; I could cg^ainly infer, that the fame River was raifcd
in f //a thofe fame CiToi fevcn Braces. And that which I lay 01
is true of all Rivers that fall into the Sea. Which thing
being true, it is nece^^ary to make great account of every fmall
rifine that Yiiimemorto maketh towards the Sea-fide by fal^
ling into Sm/ji<;. For although the rifing oi Vmmc morto,
being to difgorge its Waters into Sercfc/c , towards the Sea , were
onely a quarter of a Brace i we might very well be fure, that fare
from; the Sea, about and upon thofc fields the rife fliall be
much greater , and (hall become two or three Braces : And be-
caufe the Countrey lycth low, that fame I'lie will caufe a conti-
nual lnnundation of the Plains, like as it did before ; I caufed the
Mouth to be opened into the Sea. And therefore I conclude
that the Mouth of F/Hwe morto^ ought by no means to be opened
into Sercfoio. but ought to be continued into the Sea , ufing all
diligence to'keep it open afcer the manner aforelaid, fo loon as
ever the Wind (hall be laid. And if they (hall do otherwile, I
confidently affirm, that there will daily follow greater damages ;
not onely in the Plains , but alfo in the vvholefomnefs of the
Air •, as hath been fcen in times paft. And again. It ought with
all care to be procured, that no waters do by any means run or
fail from the Trench of Libra, into the Plain of P//<», for thcic
Waters being to difchargc into Yiume morto , they maintain it
much higher than is imagined, according to that which I have de-
lUonAratedininyconfiderationupon the ftate of the Lake ot
Venice. I have faid but little, but I fpeak to you, who under-
flandeth much, and I fubmit all to the moft refined Judgment ot
our moft Serene Prince Leofold^ whofe hands I befeech you in all
hamility to kifs" in my name, and implore the continuance ot hjs
Princely favour to me i and fodcfiring your prayers to God tar

me J I take my leave. „

Tour inojl aptHonate Servant,

Kome %• Feb*

jg^j. D. Benedetto Castelli.

The

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

0/ R U N N I N G VV A T E R So

The anfwer to a Letter written by B ar-
TOLOTTI, .touching the
difficultyes oblerved.

The fermer part of the Letter is omitted^ and the difconrfe
beginneth at the jirfi Head,

ANd fir ft I fay, Whereas I fuppofethat the level oi the Ser-
chie is higher than that of Finme morto , this is moft true,
at fuch time as the waters of Fiume morto are difcharged in-
to the Sea j but I did never fay that things could never be brought
to that pafs, is that the level ofFiume morto (hould be higher than
Serchio : and fo I grant that it will folIow,that the waters of
FiHme morto ' {h2M go into Serchio^ and its very poffible, that the
Drain of Fiume morto into Serchio may be continuate *, and I far-
ther grant, that its poffible, that the Serchio doth never difgorge
thorow Fiiinte morto towards Pifa ^ Nay, I will yet farther grant
that it might have happened, that Fiume morto might have had
fuch a fall into Serchio^ as would have fufficed to have turned
Mills : But then I add withall, that the Plains of Fifa^ and the
City it (elf muft be a meer Lake.

2. Signore ^artolotti faith confidently, that when the Sea fwel-
lethby the South- Weft, or other Winds, the level of Serchio \n
the place marked A in the Piatt, diftant about aoo. Braces,rifcth
very little : Bwt thuFinme morto in D, and in E, many miles
more up into Land rifeth very much, and that certain Fifliermeri
confirm this, and (hew him the fignes of the rifing of the Water.
I grant it to be very true, and I have feen it with my own eyes :
But this cometh to pafs, when the Mouth of Fiume morto is ftopt
up by the Sea ^ as I (hall fliew by and by. And this rifing near
the Sea-fide, is of no confiderable prejudice to the fields, hni,
this is as much as I find to be true in the aflertion of Signore Bar-
tolotti , ( without his confirming it by any other proof \ as indeed
it needs none) That the level of Fiume war/c? rifeth in E, and ma-
ny miles farther upwards it rifeth much; nor did 1 ever affirm the
contrary.

3. Concerning the difficulty of opening the Mouth oi Fiume
morto into the Sea, that which // Cafiellano faith is moft certain >
namely, That at the critrance upon the opening of the Mouth, it
is neceffary to make a deep Trench : But I fay, that at that tim^^
it is difficult to open it, unlefs upon great occafion&j for that the

Mmmm i JiSicurty

Of the Mensuration

Lik^

difficulty proccedeihfrom the waters of ?iHt»e morto being low,
and the fields drained. . . ,,

4 As to the particular of the Caufes that you tell me men
preTs fo much unto the moft Serine Grand Dnke, and to the
Prince, I have not much to fay, becaufe it is not my profcffion i
nor have I confidcred of the fame : Yet I believe, that when the
Prince and his Highneffe fee the benefit of his People and Sub-
iefis in one fcale of the Ballance, and the accomodation ot
Huntfmenin the other, his HighnelTe will incline to the profit
of his fubjeas i fuch have 1 alwayes found his Clemency and
Noblencffeof minde. " But if I were to put in my vote upon
thisbufinefle, I would fay, that the points o^ Spears, and the
mouths of Guns, the yelping of Dogs, the wilyneffc of Huntf-
men who run thorow and narrowly learch all thofc Woods,
Thickets and Heathes, are the true deftroyers of Bucks and
Boares, and not a little Salt-water, which fetleth at laft m fome
low places, and fprcadeth not very far. Yet neverthelefle,! will
not enter upon any fuch point, but confine my felf Tolely to the
bufmefTe before me.

< That Experiment of joyning together the water ot ttnme
morto, and that of Serchio by a little trench to fee what advaii-
tage the Level E hath upon the Level I, doth not give me lull
farisfaaion, taken fo particularly, for it may come to pa{re, th at

fometimes E may be higher, ai^d fometimes A lower, and I do
not aueftion but that when Serchio is low, and Ftnme morto tull
of Water, the level of Fi»w,e morto will be higher than that ot
Serchio: But Serchio being full, and Finme morto fcant of Wa-
ter the contrary will follow, if the Mouth ftall be opened to
the' Sea. And here itftiould feem to me, that it ought to be
confidcred, that there is as much advantage from E to the Sea
through the little Trench opened anew into Serchto, as from E to
the Sea by the Mouth of Fiumt morto. But the difficulty (which
is that we are to regard in our cafe) is, that the courfe of the
Waters thorow the Trench is three times longer than the courfe
of th- Mouth of Fiitms morto, as appeareth by the Draught or
PlatwI^hich you fent me, which I know to be very exaftly drawn,
for that the fituation of thofe places are frefli in my memory.
Here 1 muft give notice, that the waters of Finme morto determi-
ning thorow the Trench in Serf fcfo (the waters of which Fiums
»«orf<;arc,for certain, never folow as the Sea) their pendency or
declivity (hail, for two caufes, be leffe than the pendency of thole
waters through the Mouth towards the Sea, that is, becaule ot
length of the line through the Trench, and becaufe of the
height of their entrance into Serchio, a thing which is of very
great inipottiadlfcharging the waiters which come fuddenly, ^

6>/ Running Waters.

he (hall plainly fee, who fliall have undcrftood my Boole cf the
Meafure of Running W aters And this was the Rcafon why all
the Coiintrey did grow dry upon the opening of the Mouth into
the Sea. And here I propofe to confideration that which the Pea-
fan ts about Z*//^ relate, namely, That the Water in the Fields
doth no con fiderabk harm by continuing there five or fix, yea? or
eight dayes. And therefore ihe work of the Countrey is to o-
pen the Mouth df F//f^e ;wri:7rt'^>, in fuc^^ the Water

being come, they may have the Trench free and ready,wheh that
the Water Cometh it may have a free drain, and may not ftay
there above eight or niiie dayes, for then the overflowings be-
come hurtful. It is to be defircd alfo, that if any Propofition is
produced touching thefe affairs, it might be propounded the iholl
diftinftly that may be poflible, and not confift in generals, eipe-
cially when the Difpute is of the riffrtgs,of velocity, of tardity,
of much and little water j things that arc all to be fpecified by
meafures.

6. Your Letter faith, in the next place ? that Signore Barta-
lotti confelTeth, that if the Mouth of the ^inme morto might al-
way es be kept open, it would be better to let it continue as it is :
the which, that 1 may not yield to him in courtefie , I conlFeffe,
for the keeping it ftopt on all fides would be a thing inoft per-
nicious. Butadmittingof hisconfeffion I again reply, that Fi-
nme morto ought not to be let into 5crrfc/(?, but immediately in-
to the Sea ^ becaufe although fometimes the Mouth to Sea-
wards be ftopc up, yet for all that, the raifing of the Bank above
the Plains (which is all the bufincffe of imjportance) fliall be ever
lefTer, if we make ufe of the Mouth leading to the Sea, than
fing that of Serchio,

7. I will not omit to mention a kinde of fcruple that I have
concerning the pofition of Sign, Bartolotti, that is, where he faith
that the two Mouths A and D are equal to the like Mouths Into
the Sea ; Now it feems to me, that the Mouth A of ¥iume morto
into Serchio is abfolutely within Serchio^ not can it be made low-
er, and is regulated by the height of Serchio : But the Mouth
of fiume morto terminates, and ought to be underftood to ter-
minate in the Sea it felf, the loweft place. And this I believe
was very well perceived by Sig, Bartolottz^ but I cannot tell why
hepaftit over without declaring it : and we fee not that the
Mouth D fallcth far from the Sea, which Mouth ought to be let
into the Sea it felf, and fo the advantage of the Mouth into the
Sea more clearly appeareth.

8. That which Sig. Bartolotti addeth , that when it is high
Waters, at fuch time as the Waters are out, and when Witids
choak upF/;f ?^^^ mrto^ they not only retard itp but retMfi' ^he

Oftb€ M E N s u K A T I o n; Lib 2.

couife of. the Waters upwards very leafurely, perfwadeth me
more readily to believe that Sig, Bartolotti knoweth very well,
that the Mouth of fiumemorto let into Serchio is hurtful : for
by this he acknowledgeth that the Mouth towards the Sea doth
in fuch fort drain the Countrey of the Waters, as that they be-
come very low j and therefore upon every little impetfis the wa-
ters turn their courfe : And from the motions, being exceeding
flow , is inferred , that the abundance of Sea-water that Com-
eth into ¥iHme morto^ isfo much as is believed, and as Sig. Bar-
tolotti affirmeth.

^. After that S/^. bartolotti hath faid what he promifcth a-
bove, namely, that when the Windes blowing ftrongly do ftop
up FiHwe morto, and not onely retard but turn the courfe up-
wards, the time being Rainy, and the Mouth of Fiume morto (hut
up, the Waves of the Sea pafle over the Bank of Yinme niorto\ at
that time, faith S/g/w^ BjrJ(?/(?/^i, theChampain fliall know the
benefit of Fiums morto difcharged into Serchio^ and the mouth A
fliall ftand alwayes open j and Fiume morto may alwayes con-
ftantly run out, as alfo the Rains and Rain-waters, although the
hurtful Tempeft fliould laft many dayes, &c. And I reply, that
all the Art confifts in this j for the benefit of thofe Fields doth
xiot depend on, or confift in faying, that Fiume morto is alwayes
opcn> and Fiume morto draineth continually j But all the bufi-
nefle of profit lyeth and jconfifteth in maintaining the Waters
lo^v in thofe Plaines, and thofe Ditches, which fliall never be cf-
feficd whilft the World ftands,if you let Fiume morto into Ser-
€hio j but yet it may, by opening the mouth into the Sea : and
fo much reafon and nature proveth, and (which importeth) Ex-
perience confirmeth.

I o. In the tenth place I come to confider the anfwer that
was made to another Propofition in the Letter which I writ to
father Francefco , which prudently of it felf alone might ferve
to clear this whole bufineffe. I faid in my Letter, That great
account is to be made of every fmall rifing and ebbing of the
Waters neer to the Sea in Fiume morto^ for that thefe rifings and
fallings, although that they be imall neer to the Sea-fide, yetne-
verthelefle, they operate and are accompanied by notable rifings
and fallings within Land, and far from the Sea-fide, and I have
declared by an example of Arno^ in which a Land-flood falling,
that made it increafe above its ordinary height within Ptfa fix or
feven Braces, that this height of the fame Flood becometh ftill
IcfTer, the ncerer we approach to the Sea-coafl:s. Nor fliall the
f^id River be raifed hardly half a Braces whereupon it neceflf-
rily f^loweth, that if I fliouId return to the Sea-fidc, and tiot
knowing any of that which happeneth at Fifa, and feeing

(5/ R U N H I N O VV A t E k s.

the River Arrto raiicd by 1 Land-flood half a Brace, I tn'tght con-
fidently allirm the laid River to be raifcd in Pifa thofe fix or fe-
Ven Braces, &c. From fuch like accidents I conclude in the fame
Letter, that it is nccefliry to make great account of every little
rife that Fritffte morto (hall make towards the Sea. Now cometb
Bdrtolotti (^nd perhaps becaufe I knew not how to exprefs my
felf better, underftandeth not my Propofition) and fpcaketh that
which indeed i^ true, but yet belides our cafe : Nor have 1 ever
faid the contrary ; and v^ithall doth not apply it to his purpofe.
Nay I fay, that if he had well applyed it, this alone had been ai-
ble to have made him change his opinion. And becaufe he faith,
that I laid, that it is triic, when the abatement proceedeth from
fomc caiife above, as namely by Rain, or opening of Lakes;
But when the Caufe is from below, that is, by Ibme flop, as for
inftance fomc Filbers VVears or Locks, or fome impediment re-
mote from the Sea, although at the Level it (hall rife fome Braces
where the impediment is, yet that riling ftiall go upwards; and
here he finiflieth his Cifcourfe,' and concludeth not any thing
itlore. To which I fay firft, that I have alio faid the fame in the
Propofition, namely, that a Flood coming (which maketh Arno
to rife in ?ifa fix or feven Braces (which I take to be a fuperiour
Gaufe whether it be Rain or the opening of Lakes, as beft plea-
feth Bdrtolottt) in fuch a cafe 1 fay, and in no other (for towards
the Sea-coafts it (hall not caufe a rifing of full half a Brace ; and
therefore feeing Amo at the Sea- fide to be raifed by a Flood, whe-
ther of Rain, or of opening of Lakes half a Brace) it may be
inferred, that at Vifa it (hall be raifed thofe fix or feven Braces ;
Vvhich <J*aricty, well confidercd, cxplaincth all this affair in favour
of my opinion : For the rifing that is made by the impedimerit
placed below, of Fifliing Wcares and Locks, opera.teth at the be-
ginning, raifing the Waters that. are neer to the imp(?diment ;
and aftervvards lefs and lefs, as we retire upwards from the im^
pediment : provided yet that we fpeak not of a Flood that com"
meth by accefllon, but onely of the ordinary Water impeded.
But there being a new accefllon, as in our cali, then the Water
of the Flood, I fay, fliall make a greater rifing in the parts fuperr-
our , far from the impediment j and thefe impediments fliall
Come to be thofe that fliall overflow the Plains, as happened
eighteen or nineteen years ago, before 'the opening of Finm
,niorto into the Sea, The fame will certainly follow, if Fiume
mortohcletinto Serch/o: Here I could alledge a very pretty
cafe that befell me in la " Campagna di Koma^ necr to the Scar-
fide, where I drained a Bog or Fen , of the nature of the Wa-
ters of P/p, and I fucceedcdin the cnterprizCjthe Waters in their
fire towards the Sea abating only three Palmes, and yetjin the

Fen

" The Countrey

or Province lyin^
round the Ot^-,'

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2°K.B. 9,163

Oftbe

Mens UR At lOK lih^^.

Fen they fell more than fifteen Palmes. But the b^fi^icfft
would be long, and notfoeafily to be declared, and I sjm cer-
tain that Sig. Bartolotti having confidered this, would alter his
iudsment, and withall would know that remitting that impedu
ment anew, which 1 had left for lelfe than three \ almes towar^^
the Sea, the Waters in the Fen would return with the firft Floods
and Raines to the fame height as before , as likewile Fiume mm
will do if it (hall be let again into S erchie.

Here I intreat your Honour to do me the favour tqimportunp
P. fra/;/:fr<:oinmybchalf,that hewould be plcafed to declare
my meaning in the aforefaid Letter to Sig. Bartolotti, for I hope
that it he villi underftand this point, he will be no longer fotes
nacious in his opinion.

Next that thefe Lords in the Commiffion of Sewers, with tji^
Right Honourable the MarquclTe of S. Angelo, and your Hpngur
do approve of my judgment, doth very much rejoyce me but
becaufe that I know that they do it not in defign to complemei^i
me, but onely to ferve his Highnefs our Grand Duke, I freely
profefs that I will pretend no farther obligations from them there-
in,than I account my felf to owe to thofc whofe opinions
contrary to mine, for that I know that they have the fame ppfi.
The definitive fentence of this whole bufinefs is, that they give
thefe Plains, thefe Draines, and thefe Waters farre fetcht api
pellations.

11. As to the quantity of the Water that Finme mom drtv
chargeth into the Sea, there are very great difputes about it,ati4
I have been prefcnt at fome of them. But let your Honour be-
lieve me, that as this is not continual, but only during a few
dayes, fo it will never be of any great prejudice to thefe Fields j
and if your Lordfliip would be afcertaincd thereof, you may
plcafe tdgo to Finme morto at about a mile's diftance from the
Sea, in the time of thefe ftrong Windes, and obferve the curr
rent ffom thence upwards, for you fliall finde it extrcam flpvy?
and confequently will know that the quantity of the Water thaf
is repuls'd is very fmall. And this fcems to be contradi6led by the
rule of Rifings proceeding from caufes below, which occafiqn n9
eonfiderabk alteration far from the Sea.

I am neceffitated to go to morrow out of Rome with bis Emi.-
iieuce Cardinal G<?e>ii«o about certain affairs touching Waters,
therefore I (hall not farther inlarge, but for a clofe to this tedipu^.
Difcourfe, I conclude in few words, that Ftume morto \s by
means to be let into Serchio, nor are there any means intermedir
ate eourfes to be taken, for they will alwaycs be prejudicial 3 buf
tinme morto is to be difcharged immediately into the Sea- Whe^
ft is fW>ptupby the fury of the Sea- waves, I affirm that it is *

ey
te
Cl
lo
K

th
fo

ne
>13

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2°K.B. 9,163

Lib

Of R

UN N I NG

A T £ R

fign that there is no need of opening it j and if there be any oc-
caiion to open it, it is ealily done. As for the reft your Lordfliip
may pleafe to keep account of all the jparticulars that occur ^ foi^
the memory of things paft is our Tutreffe in thofe that are to
Gome. If occafion fliall offer, I intreat you to bow humbly in
my name to His Highnefs the Grand Duke, and the moft Serene
Prince Leopold'^2ind to attend the ferviceof Their Highneffes, for
you ferve I rinces of extraordinary merit , And to whom I my
felf am alfo exceedingly obliged. In the controverfies thatarife
refpeS the pious end of fpeaking the Truth, for then every
thing will lucceed happily. 1 kifs the hands of Padre FrancefcOy
of S/g. Bartolotti , and of your Lordfliip.

R(?;;/f5 14. March i6j^'i'

Tour Hononrs
moH Obliged Servant
D.BENEDETT 0 CASTELLI

't/pon this occafion 1 will here infert a Difcourfc that 1 made
^ upon the Draining and improvement of the Pontine Fens,
for that I think that whatfoever may be done well and to pur-
pofe in this matter hath abfolute dependance on the perfeft know-
ledge of that fo important Propofition, by me demonftrated and
explained in my Treatife of the Menfuration of Running fVa-
ters , namely, That the fame water of a River doth continually
change Meafurcs, according as it altereth and changeth the ve-
locity of its courfe , fo that the meafurc of the thickncffe of a
River in one Site, to the mealure of the fame River in another
Site, hath the fame proportion reciprocally that the velocity in
this fite hath to the velocity in the firft fite. And this is a Truth
foconftant and unchangeable, that it altereth not in the leaft
point on any occurrences of the Waters that change : and
being well underftood, it openeth the way to the knowledge of
fundry advectifements in ihefe matters, which are all refolved by
this fole principle h and from it are derived very confidcrable be-
nefits i and without thefc it is rmpoffible to do any thing vvith'
abfolute perfeftioa

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2°K.B. 9,163

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2°K.B. 9,163

Liki.

CONSIDERATION

Upon the

DRAINING

OF THE

Pontine Fenns.

D. BENEDETTO CAS TELL I, Abbot
ofS'BENEDEtToALOisicand Profeflbr
ofthcMatkmaticksto V.Vrkn VlII. in the
Univerfityof KO ME,

C ON S IDERATI ON

, Mongft the encerprizes by me efteemed, if not ab-
(olutely impofliblc, , at Icaft exceeding difficult,
one was thitt famous one of Draining the Pontine
Ycnns , and therefore I was fhorowly refolved
iiever to apply my minde thereunto , although
by my Patrons I fliould be cbmmanded to the
fame : accounting th.it it was an occafioh rather of lofing repu-
tation by the mifcarriage of the attempt, than of giinifig fame by
reducing things to a better pafs then they noWare at. Yet ncver-
thelefs,having of late years obferved the place5and failed through
thofe Ch^nclsjand thofe Watersjafter I had^ made fomc r^flefiion'
thereupon, I thought that the enterprize was not fo difficult a:s'
I had at fii ft conceited it to be > and I am the mote confirmed irf
this opinion, upon the indudenient of that Which I have v^rittext'

N't! iVri 2r ^et»C'

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2°K.B. 9,163

Of the Mensuration; Lih.^.

Geometrically in my Trcatife of the Menfuration of Running
Waters, fo that talking with feveral peifons, I adventured to
affir^vindifcojpres-i, tlmt thi^-improvefiflei^jt iuigbt^oflibIy43c
broi^htiAtdPa|oaacflSte. - » ^ - ^ -

Now 1 have refolved to fet down my thoughts in writing , and
to honour this my Paper wrohnciie Ntyble>Name of your Lordfhip,
to render it the more credible and cohfpicuous at the firft view,
if it ft-dt^d chance that the Sub^a I treat of, wcie not of fuch
mommas th^^lt did dcferv€^to'= be valued for any^other reafon.
PardorTme, Sir, if I have been too bold, and continue me iiV the
number of your Servants., j,-, j ,

Theenterprize ofDrainmg a great part of the Territories of
the Vontine Fenns^ hath been undertaken both in ^the time ot
thcantientKe^;»/iWi-,and laftof all,inour days-, yeavin»the late
times by St)ctHS-V, I do not doubt in the leaft, but tJiat it will
be poffible yet to reduce things to a very good pals^and if I be not
miftaken, with a very fmall charge incomparifon of the profit that
would be received from thofe rich Grounds. This improvement
was.^^lgreate5g>eficpiftthe tiiB&of^/^^ by rear

fon the\hing was not rightly underftood, tliere were made many
DU^&?<^ gifei^f^t^o^ '^W^ Vain: and

amongfrCo many? operations, there hapned fome to be made that
fucce^'d,iVwas c^e(ired but not being unde they were

held in noaccoiiniiiand thusthebu-fin^is being ncgleded , the
waters are returned into the fame ft ate as they were at firft, be-
fore the improvement. Here 1 have by familiar difcourfes
with my friends, explained this cnterprizc undertaken by S/x-
tus V. and haply aifo by fome more antient, with the example of
the ^2h\^oiOrilo^\n Ariofio. This Monfter was made upwth
fuch enchantment, that men fought with him alwayes in vain,
for though. in the Combate he were cut in pieces , thole divided
lV|^miferspreferitK returned to» the fight more

fierce 'theH Wthe taladine Afiolfo coming to undertake

him, altera long difpute , at the end he cut his head flieer oft'
^6m ttieftiouldersat oheblow:, and nimbly alighting from his
fjbrfe,tppkiheMonftrous and mounting again, as he rid
away he fell to Ihave the Pole of that Monfter , and fo he loft
the Locjc ot I^air, in which alone the enchantment lay 9 and then
the horrtble Head inaninftant manifeftcd figns of death, and the
trunk which ran, feekingto reunite to it anew, gave the laft gafp,
and in this manner the enchantment ended. The Book of Fate
ferved admirably to the Paladine .whereby he came to under-
ftand that Charm ; for by fliaving his whole head, the enchanted
hairs came to be cut ofFamongft the reft : In the fame manner,!
fay, that it hath fometimes happened in Draining thofc Fields^

Lib. 7. Of R U NN I NCj Waters.

tor that amongd fo many tryals as have been ma^e , that alfo
was light upon, on which the improvement and remedy to the
dilbrder did depend. And to us my fore-named Treatife fh^ill
lerve for a Rule, which being well understood, fliall make us to
know wherein confiftcth, and whereon depcndeth this mifcarrir
age, and confeqiicntly it will bceafie tp apply thpreUr^to a fea^f^-
nablcremcdy.

And firft 1 fay^Tbatf therq i^.no doubt but tl)a|: th^ wa^tcxs
continue fo high on thofe Plains becaufe they are lo^ high in the
principal River , which oughuo receive them, ancj, carry theni
into tiiq Sea. Now the Caufes of the height of the River, ma^;
in my judgement be reduced to.one alone , which is that by
fo oiteamentioncd for the moft Potent onp, and declared in my
afore-n^m^dTraa.ate h to wit, Thq tardity of the motion of the
wat^rs^whichdochalwayesi-nf^hbly, and precifely caufc tl^e
felffame Running Water to change the meafure of its thickjQ^ft
at fuch a rate, that the more it encreafcth in velocity ^ tlie more
iC decreaftth in meafure and the more it decreafetKin velocity,
tte more ic enerq^feth in meafure : As for example , Ita Riyer
run io fuch a place with the velocity of moving a mile in the
fpace of an hour, and afterwards th,e fame River in aiipther plac^
doth encreafe in velocity, fo as to make three miles an hour ;
that fame River (halidiminifti in thicknefs, two thirds. : ^nd on
the contrary, It it (hall diminifc in velocity fo, as that it runneth
but half a mile in the fame time, it (hall encreafe t|^e double in
thicknefs and meafure. And in a word , look what proportion
the velocity in the firft place, hath to the velocity jn the fccpnd,
and fuch hath reciprocally the meafure of the thicknefs in the
fecond place, to the meafure in the fii ft ^ I ^l^^^'y demon-
ftrated inmy Tieafife : Which I repeat fo frequently , that I
fear the Profelfors of Polite Learning will charge me with Tua-
tologie and vain Repetition. But 1 am fo defirous in this moft
important point to be well undcrftood , becaufe it Will then be
eafie to comprehend all the rcft^ without this it is impofflble
(1 will not fay diflScult, but absolutely imppffible) to underftand,
or evertoefFea anything to purpofe. And the better to ex-
plain the example, let it be fuppofed.
That the water of a River A

runneth high at the level of A F, aL- — — 'F

with fuch a certaiii yelgcity :,,a^)4 kt
4t,by the fame water,l?e velocitated R
thi^e times more h I i^y, that it will

^batCT , and fliall ftwid^t the jcyel C.^_ — D

ibBE^and if it fiiall more vclpci- : • - . .....

t^c^ it ^ili.abate th^morc^^t die Scii Bw tf it #CHil4 r€;tit^^

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2°K.B. 9,163

Of the Mensuration Ub.2.>

mote than it did at the level A F, it would rife yet iliore above
the faid level A F 5 although that the lelf lame quantity of water
lunnethall the while. By the above-named folid Piihciple I
refolve extravagant Problems in my Treatiifejand affign the Rea-
fons of admirable efFefls of Running Waters : But as for what
cOncerneth bur purpofe of the Pontine Fenns^ we have the Cau-
{es very plain and clears for which, by the trampling of Cattle
which pafs thorow the Draining Kiver^ the waters abate fo nota-
bly, that it is as ic were a miracle for thofe Reeds , Flags, and
Weeds that fpring up, cncreafe, and fpread all over the River,
ftop and impede that velocity of the waters which they Would
have by means of their dechvity. Bilr that pafl'age of thofe Beafts,
treading down thofe Weeds unto the bottom of the River, in fuch
fort, as that they no longer hinder the Current of the Water j
and the fame Waters increafing in their courlc ^ they do dimi-
nifli in meafureand height jand by this meanes the Ditches of the
Plains empty into the fame fuccefsfully , and leave them free
from Waters , and Drained. But thefe Weeds in a fliort
time fprouting up anew, and raifing their ftalkes thorow the
body of the Waters , they reduce things to the fame evil
ftate , as before, retarding the velocity of the Water, ma-
king it to increafe in height , and perhaps do occafion grea-
ter mifchiefsj feeing that thofe many knots which each plant
flioots forth, begets a greater multitude of Stalks , which much
more incumbering the Water of the. River, are a greater impe-
diment unto its velocity , and confcquently make the height
of the waters to ericrcafefo much the more, and do more mifchief
than before.

Another head to which thefe harms may be reduced, but pro-
ceeding from the fame Root, which hath a great part in this
diforder, is the impediment of thofe Wears in the River which
are made by heightning the bed of the fame, for placing of fifli-
irig-nets j of which ?/Jcanes I reckoned above ten, when I made
a voyage thorow thofe waters to Sandolo. And thefe Fifliing-
Wears are fuch impediments, that fome one of them makes the
w^ter o{ the River in the upper part to rife half a Palm , and
fometimes a whole Palm, and more ^ fo that when they are all
gathered together, thefe impediments amount to more than feven,
or pofiibly than eight Palms.

There concurreth for a third moft Potent Caufe of the waters
ccintinuing high in the evacuating, or Draining Chanel, and con^-
fcquently on the Plains , The great abundance of water that iffu-
tth from Finme Sifioy the waters of which do not keep within its
Banks when they are abundant j but encreafing above its Chanel,
they uiiitt with thofe of the Evacuatorj and difperfing thorow

the Fens are raifed with great pre)udicej and much grei-
tcr than is conceived ^ iccordmg to what hath been d^htb'rf-'
ftrated in the Second Oonfidei atidii upon xht Lak^ of Vcnici'l
Nor is it to any purpofe to fay, that if We flioirld rtv^affifi'^
all the Waters that disirnbogue ixoin Ftnme Sifio , '^i^Hier
tJiemintO 'oW'fnnrfme , vveflioiiW finde them' t6^ • bti jtiii6R|
as that tliey (hall bb able to nia^e^ the Wakei^s 6f tHfe^-fettb
to increafc , by r^afon of the- ^^Hd expaiiififerf thtiii ^ ov^^i?
wh ich that bcVdy 6f' water to yifteiid^-' fer Wt\fii' 'ittfi^m^i^
anfwer With that which^ We have giveh iK^tkd^^^kiHhfe^Fitfft^'Cafl^
fideration touching the L'^A^^f ^r^fiice^ i^'t^Anf^ xW mi^
menc that i^ canfed by tiie jB^e^^litft^iWtc^^ell^afe And itibt-e^
over, if I (hill ad^b-^the+etb t'lM'^wlkh^P WiJ^^JftieKt ^S^oritl
Confideration, it will be very apparent how greatly •Iftftr'JbfiSfflF
and prejudicial thefe excurfions of Waters from Yiume S:Jio
may be , which are not kept under, and confined within the
River : Therefore , proceeding to the provi lions , and ope-
rations that are to be accounted Principal] , I reduce them to
three Heads,

In the firft place it is iieceffary to throw down thofe Weares,
and to take the Pifciaries quite away, obferving a Maxime, in
my judgment, infallible, that Fifhing and Sowing are two things
that can never confift together j Fiftiing being on the Water, and
Sowing on land.

Secondly, it will be ncceffary to cut under Water in the bot-
tome of the River thofe Weeds and Plants that grow and in-
creafe in the River, and leave them to be carried into the Sea by
the Stream ; for by this means thefe Heeds (hall not fpring up
and diftend along the botcome of the River, by means of the
Beafts treading'uponthem j And the fame ought to be done
often, and with care , and muft not be delaied till the mif-
chief 'increafe, and the Champain Grounds be drowned, but
one ought to 'order matters fo, as that they may not dro\Vn.
And I will affirm, that otherwife this principal point would be-
come a moft confiderable inconvenience.

Thirdly,it is neceifary to make good the Banks of F/wwe SiJlS
on the left hand, and' to procure that thofe Waters may run in
the Chanel and not break forth. And it is to be noted, that
It is not enough to do one or two of thofe things, but we are to
put them all in execution ; for omitting any thing, the whole
machine will be out of tune, and fpoilcd. But proceeding with
due care, you (li all not only Drain the Pontine Fens , but by
means of this laft particular the Current of Fium Si^lo fhalf
fcowr its own Chanel of its felf, even to the carrying part of ic
away : and haply with this abundance of water that it fliall

Of the M'ENSURATiON Lil). I,

bear, the Mouth iiella Torre may be opened, and kept opert
into the Sea. An(3 it would, laft of all, be of admirable bcne-
fit to ckanfe fi^^Wf ^/ffe? from many Trees and Buflies where-'
with it is overgrown. - ;

And with this I conclude, that the Improvement or Drain
poffiblc to be made confifteth in thefe three particulars. Firft
in taking away the Fifliing Weares, leaving the Courfe
of the Waters free. Secondly, in keeping the Principal
Rivera clear frooi Weeds and Plants. Thirdly , in keeping
the water of Finpte SiSio in its own Chanel. All which are
things that may be done with very little charge, and to the
inanifeft benefit of the whole Country, and to the rendering
the Air wholfomer in all thofe Places adjoyning to the Foa^^
tine Fens.

CONSIDERATION

Upon the

DRAINING

Of the Territories of

Bologna, Ferrara,

A ND

Romagna.

D. BENEDETTO CASTELtl, Abbot
<)f S. Benedetto Aloisio, Mathematkm
to P. ■V,km VIII. and Profeflbr in the

Univerfity of R 0 M E.

He weghty bufincffe of the Draining of
the Territories of Bologna , Ferrara^
and Komagna having been pua£);ually
handled and declared in writing from
the exceUem memory of the Right Ho-
nourable and Noble Monftgnore Corfini^
who was heretofore Deputed Commif-
iaiy General, andVifitor ofthofeWa^
ters V Ism not able to make fuch ano-
ther Dii^ou rib upon the fame Sub^eft, but will only fay lx)me-
what for farther confirmation of that which I have faid^in this
Book upon the Lak^ of Venice^ upoii the Pontine F ens ^ ^^nd up-
on the Drainmgof ihofePlains of P//^, lyiBg between the Ri^
ter$ Arno^wdSsrchio 'y wlmeby it is manifcft, that in all the

O o oo afore^^

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2°K.B. 9,163

Ofri&<?MENSURAT ION Uk t

aforementioned Cafes, and in tfie prefent one that we are in hand
with, there have, in times paft, very groffe Errours been com-
mitted, tlirdugh the ndt having ever vircll undcrftood the ^ue
meafure of Running waters ^ and here it is to be noted, that the
bufineffeis, that i i Verjice^ixhc diverfion of the vs aters cf the
Lake, by diverting the BrewK was debated, and in part executed,
withoTKconfideration had how. great abatement of water might
follfw |i the Lake, if the Bi^>l^ were diverted, as 1 have ftiewn
in the^'firft Confideration upoti this particular, from which aft
there hathinfued very bad coi^fequciices, not only the difficulty
of Navigation, bat it hath inlFectcd the wholfomneffe of the Air,
and can fed the ftoppage of the I orts of Venice. And on the
contrary^ the fame inadvertency of not confidcring what rifing of
the Wafer the Retto^ and other Pvlvcrs being opened into the Val-
leys of Bologna ^nd F err ardj might C2iuk in the faid Valleys, is
the certain caufe that fo many rich and fertile Fields are drown-
ed underwater, converting the happy habitations and dwellings
of men into miferable receptacles for Fifties : Things which
doubtleffe would never have happened, if thofe Rivers had been
kept at their height, and Keno had been turn d into Main-Poy
and the other Rivers into that of Argenta, and of V olano* Now
there having fuflScient been fpoken by the above-named Uonfig.
Corfini in his Relation, I will only adde one conceit of my own,
which after the Rivers fliould be regulated, as hath been faid, I
verily Jaelieve would be of extraordinary profit, I much doubt in-
deed that I (hall finde it a hard matter to perfwadc men to be of
my mind, butyet neverthelefs I will not queftion, but that thofe,
atleaft, who fliallhave underftood what 1 have faid and demon-
ftrated concerning the manners and proportions, according to
which the abatements and rifings of Running waters proceed,
that are made by the Diverfions and IntroduSions of Waters,
^ill apprehend ^hat my conjefturc is grounded upon Reafon-
And although I defcend not to the exaftnelTe of particulars, I
willopenithe way to others, who having obferved the requifitc
Rules of confidering the quantity of the waters that are intro-
duced, or that happen to be diverted, fliall be able with punftu-
alicy to examine the whole bufineffe, and then refolve on that
which fliall be expedient to be done.

Reflefting therefore upon the firft Propofition, that the
Rifing? of a Running Water made by the acceOTion of new water
into the River, are to one another, as the Square -Roots of the
quantity of the water that runneth ; and confequently, that the
Cime Cometh to pafs in the Diverfions : Infomuch, that a River
running in height onefucha certain meafure, to make it encreafc
double in height, the water is to be cncreafedto three times as

much

Lib.

Of Running VV a t e r Jj;-

much as ic ran before ^ fo that when the water (hall be quadru-
ple, the height (hall be double ^ and if the water were centuple^
the height Would be decuple onely, and fo from one quantity
to another : And on the contrary, in the Diverfions, If cf the
lOQ. parts of water that run thorow a River , there (hall be di-
verted , the height of the River diminiiheth onely , and con-
tinuing to divert t«t , the height of the River abateth Itkewife 5
and fo proceeding to . divert and then ' 5 and then ^ and
then "I, and then ^5', and then t^^, and tHen ~J, alwaies by
each of thefe diver fions, the height of the Running Water di«
miniflieth the tenth part: although that the diverfionsbe fo une*
qual. Reflefiing I fay upon this infallible Truth, I have had a
conceit, that chough the Kerio and other Rivers were diverted
from the Valleyes, and there was onely left the Chanel of Na^i^i-
^^^/f?//, which was onely the part of the whole water that fa 1-
leth into the Valleys^ yet neverthelefs, the water in thofe fame
Y^U^ycs would retain a tenth part of that height that became
con;oyncd by the concourfe of all the Rivers : And therefore I
fhould think that it vi'ere the beft refolution to maintain the Cha^
nel ofNd'z^igattori (if it ivere poffible) continuate unto the ?o of
Fcnara^ and from thence to carry it into the ?o of Volano 5 for
befides that it would be of very great eafe in the Navigation of
Bologna^ znd Ferrara , the faid water would render the ?o of
Volano navigable as fat as to the very Walls offerrara , and con-
fequently the Navigation would be continuate (vota Bologna tc^

the Sea-fide. n^ ^ r '

But to manage this enterprize well, it is neceflary to ihcalure
the quantity of the Water that the Rivers difcharge into the Val-
leys , and that which the Chanel of Navigation carryeth, in man-
ner as I have demonftrated ft the beginning of this Book ^ for thi^
dncc known, we fliallalfo come to know,how profitable this di;
verfion of the Chanel ofHamgation from the Valleys is like to
prove which yet would ftill be unprofitable, if fo be that alf
the Rivers that difcharge their waters into the Valleys, fliould
not firft t>e Drained , according to wha^ h^th been arbove ad«
Vcrtifed.

Abf)0t C A S T £ L L i, intheprefent conftderdtion referring
himfelfto the Relation of Monfig. Corfini, grounded upon the Ob-
fer'vations and Precepts of the faid Abbot-, 06 is feenin the fre-^
fent DifcoHrfe. I thought it confinement for the compUating of the
Work of our Authour, upon thefi ftibjeSlsy to infett H iHthB
place.

Oooo 2

Of the M E N s u K A T I o n; Lib,7^
A

Relation of the Waters in the Territories
of Bologna and f errata,

B y

The Right Honourable and llluftrious, Monfg^
note C O R S I N I , a Native of Tufcanj, Su-
perintendent of the general Drains,
and Prefideht of R^'/72^^//^.

THe RhcHOy and other Brooks of Komagna , were by the
advice of F. Agoftino Sperna'z»'x»att the Jefuite, towards
the latter end of the time ot Pope Clement VUI. notwith-
fiandhig the oppofition of the Bologuefij and others concerned
therein, diverted from their Chanels, for the more commodious
cleanfing of the Fo of F(?rr^ri?,and of its two Branches of Prima-
ro^ and Volano ; ia order to the introducing the water of the
M^izJ-P<7 into them, to the end that their wonted Torrents being
reftored, they might carry the Muddy-water thence into the Sea,
andrtftoreto the City tht iNavigation which was laft, as isma-
nifeft by the Brief of the faid Pope Clement^ direfted to the Cat"
ditldl San Clemencey bearing date the a a. oi Augnji^ 1 604.

The work of the faid cleaniitig, and introducing of the faid
P(7, either as being fuch in it felf, or by the contention of the
Cardinal Legates then in thefe parts |^nd the jarrings that hap-
ned betwixt them, proved fo difficult, that after the expence of
vaft lumnas in the ^ace of ai. years, there harh been nothing
done, fave the rendring of,it the more difficult to be efFefted.

Interim, the Torrents with their waters, both muddy and
clcar/have damaged the Grounds lying on the right hand of the
Vo of Argenta^ and the Kheno thofe on its Banks ^ of which I
will fpeak in the firft place, as of that which is of greater impor-
tance, and from which the principal caufe of the mifchiefs that
reiult from the reft doth proceed.

This Rfcea^ having overflowed the * Tennency o( Sanmartinai
in circumference about fourteen miles given it before , and part
of that of Cominale given it afterwards , as it were,for a recepta-
cle ^ from whence? having depofcd the rcattcr of its muddinefs,
itiffued clear by the Mouths of Mafi^ and of Lie*valoro^\nto
the Po ofPrimaro^ and of Volano *, did break* down the encom-

pafllng Bank or Dam towards S. Martina^ and that of its new
Chanel on the right hand neer to Torre del Fondo.

By the breaches on this fide it ftreamcd out in great abun-
dance from the upper part of Cominule^ and in the parts about
Ka veda^Vioggio^ Caprara^ Chiare di Keno^ Satit* Agoftino^ San
?rofperOj San Vincenz^o, and others, and made them to become
incultivable : it made alio thole places above but little fruitful,
by realon of the impediments that their Draines received, finding
the Conveyances called Kiolo and ScorfurOy not oiily filled hy la
Motta and Lt Belletta^ but chat they turned backwards of them-
felves.

But by the Mouths in the inclofing Bank or Dam at Horgo di
S. Martina IfTuing with violence, it fiift gave obftruaion to the
ancient Navigation of UJ orrc del la Fojf a, and afterwards to
the modcrneof the mouth of Ivf^/r, fo that at prefent the Com-
merce between Bologna and ¥errara is loft , nor can it ever be
in ar>y-'durable way renewed, whilft that this exceeds its due
bounds, and what ever moneys fliall be imployed about the fame
(hall be without any equivalent benefit, and to the manifeft
and notable prejudice of the * Apoftolick Chainber.

Thence paffinginto the Valley of Mari^ara , it fwclleth high-
er, not only by the rifing of the water, but by the raifing of the
bottome , by rcafon of the matter funk thither after Land-
Hoods, and dilateth fo, that it covereth all the Meadows there-
abouts, nor doch it receive with the wonted facility the Drains of
the upper Grou!ids,of which the next unto it lying under the wa^
ters that return upwards by the Conveyances, and the m^re re-
mote, not finding a paflage for Rain-waters that fettle, become
either altogether unprofitable cm- lictle better.

From this Valley, by the Trench or Ditch of Manara , or of
la Puca by la Buo^a^ or mouth of Cajialda de Rojp, and by the
new pafTage it falleth into the Fo of Argenta, which being to re.
ceiveit clear, thatfo it may fink farther therein, and receiving
it muddy, becaufe it hath acquired a quicker courfe, there will
arife a very contrary effeft.

Here therefore the fuperficies of the water keeping high, untU
it come to the Sea, hindereth the Valleys of Karjennay^hcrc
the River Senio^ thok of ^an Bernardino where SattternQ was
turned, thofe oi Bnon acqniflo , and thofe iof M^mmi?, where
the Idice^ Quaderna, Sc/i(?r a fall in, from fwallo wing and taking
in their VVaters by their ufual In-lets, yet many times, as I my
felf have feen in the they drink them up plentifully.

whereupon, being conjoyned with the muddineffe of thofe Ri-
vers that fall into the fame, they fwell, and dilate, and overflov^
fome grounds, and deprive others of their Drains in like mariner

lot

• The popes
Exchequer,

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2°K.B. 9,163

101

Of ibe Mensuration

r ToUpne is a
plat of Ground al-
moft furrounded
urith Bogs or wa-
tcrs,Ukcan liland

* People of Per-

* In Chancis
made by hand;

hath been faid of ihn oi Marrara^ inibmucii that from the
Point of S. Giorgio^ as far as S. Alberto all thole that are between
the Valleys and Fo are fpoiled, of thole that arc between Valley
and Valley many are in a very bad condition, and thole that are
fome confiderable Cpace above not a little damnified.

In fine, by raifingthe bottom or fand of the Valleys, and the
bed of Ke«(?, and the too great repletion of the P(? of Vrjmato
with waters, the Valleys of Comatchio (on which fide the Banks
are very bad) and ^ Yolefme di S.dorgiO are threatned with a
danger, that may in time, if it be not remedied, become irrepa-
rable, and at prefent feeleth the incommodity of the Waters,
which penetrating thorow the pores of the Earth do fpring up in
the fame, which they call Vnrltngs^^ which is all likely to redound
to the prejudice of Ferrara, fo noble a City of Italy-, and lo im-
portant to the Ecciefmfticl^State.

Which particulars ali appear to be attefted under the hand of
a Notary in the Vifitation which I made upon the command of
His HolinelTcand are withall known to be*true by the ^Ferrarefi
thefhfelves, of whom (befides the requeft of the Bolognefi) the
greater part beg compaffion w^ith fundry Memorials^ and reme-
diesa afwell for the mifchiefs paft, as alfo for.thofe in time to
come, from which I hold It a duty of Confcience, and of Cha-
rity to deliver ihem.

Pope Clement judged, that the fufficient means to cfFeft thh
was the faid Introduftion of the Main ?o into the Chanel of
Ferrara -y a rei'olution truly Heroical, and of no lefTe beauty
than benefit to that City , of which I fpeak not at prefent, be-
caufel think that there is need of a readier and more acco-
modate remedy.

So that I ice not how any other thing can be fo much confide-
rable as the removal of Keno^ omitting for this time to fpeak ot
* inclofing it from Valley to Valley untill it come to the Sea, as
the Dukes of Ferr^rij did defign, foralmuch as all thofe Ferra-
reft that have intereft in the ?olefine di S. Giorgio^ and on the
right hand of the ?o of Argent ti do not defirc it, and do, but too
openly, t)roteft againft it j and becaufe that before the Chanel
weremad'easfaras theSea, many hundreds of years would be
fpent, and yet would not remedy the dammages of tJiofe who
now are agrievcd, but would much increafe them, in regard the
Valleys would continue fubmerged, the Drains flopped, and the
other Brooks obftrufted, which would of neceffity drown not a
few Lands that lie between Valley and Valley j and in fine, in
>^egard it hath not from "ianUartDta to the Seaforafpace of fif-
ty miles a greater fall then 19, 8, 6, fcet,it would want that forc^
^hieh they themfelves who propound this projeS do require it to

have

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2°K.B. 9,163

Lik2.l 0/ Running Waters.

have.that fo it may not depofe the matter of the muddrncfs when
it is intended to be let into

So that making the Line of the bottome necr to Vigarano^ it
would rife to thole prodigious termes that they do make bigger,
and they may thence expcft thofe mifchiefs , for which they
will not admit of introducing it into theiaid Fo of VoUna.

Amongft the wayes therefore that I have thought of for efFcft-
inc^ that fame remotion, and which I have caufcd to be viewed by
sktlful men that have taken a level thereof, C with the afliftanee of
the venerable Father, D. Benedetto Cafielli o( Cafina, a man of
much fidelity and honefty, and no lefs expert in fuch like affairs
touching Waters, than peifeftin the Matbematkkjyi^cv^Xm^?^) Vno
onely? the reft being either too tedious, or too dangerous to the
City, have feemed to me worthy, and one of them alfo more than
the o'ther, to offer to your LordOiip.

The one is to remit it into the Chanel ot Volanay thorow which
it poeth of its own accord to the Sea.

The other is to turn it into Main-Po at Stellata^ for, as at other
times it hath done, it will carry it to the Sea happily.

As to what concerns the making choice of the firft way, that
which feemcth to perfwade us to it is, that we therein do nothing
that is new, in that it is bat reftored to the place whence it was
removed in the year 1522. in the time of Pope Adrian , by an
agreement made in way of contraft, between Alfonfo^ Duke of
Yefrajna, and the Cologne ft h and that it was diverted for reafons^
that are either out of date , or elfe have been too long time

"^"^ In 'uke manner the facility wherewith it may be efFefted , let-
tine it run into the divided P^, whereby it Will be turned to fer-
rara or elfe carrying it by Torre delFondo, to the mouth of Mtf^i,
and frotii thence thorow the Trench made by the Per rare ft,.
along by Vanaro, where alfo finding an ample Bed, and high and
thick Banks, that will ferve at other times for it, and for the wa-
ters of P^, there may a great expence be fparcd.

That what ever its Fall be, it would maintain the lame, not-
having other Rivers, which with their Floods can hinder it and
that running confined between good Banks, without doubt it
would not leave la Motto by the way ^ but efpecially , that it
would be fufficient if it came to Codigoro, where being afiifted by
the Ebbing and Flowing of the Sea, it would run no hazard of
having its Chanel filled up from thence downwards .

That there might thence many benefits be derived to the City,
by means of the Running Waters, and alfo no mean Navigation
might be expefted. , .

On the contrary it is objeacd , That it is not ccnveniej^ to

tnink

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2°K.B. 9,163

IG4

• The inch of
thefc places is
foaicwhai h'l^tt
rhan curs.

Of ibe M E N s u Fv A T 1 0 N. Lib r

think ofreturning this Torrent into the divided Pi;, by reafon of
the peril that would thence redound to this .City.

And that goingby Tc;rre del Fonda ^ ibroiigh Sanmartnia to
the Mouth de Maji by the Chap.pel of Vigara//o unto the Sea, it is
by this way 70. miles ', nor is the Fall greater than 26.5.6. Feet, fo
that it would come to fall but 4. inches & an halfjor thereabouts
in a mile i whereas the common opinion of the skilfull (to th6
end that the Torrents may not depofe their fand tJiat they bring
with them in Land-Floods) rccjuireth the twenty fourth part of
the hundredth part of their whole length, which in our cafcj
accounting according to the meafure of thcle places, is 16. inches
a* mile-, whereupon the linknig of the Mud and Sand won
moft certainly follow, and fo an imm^nfc hcightning of the Lin^
of the Bottom, and confequcntly a necefilty of railing the Bank.s^>
theimpoflibility of maintaining them, the danger ot breached
and decayes, things very prejudicial to the ijhts of this City, and
of San G/(?r^i<?, the obftrudion of the Drains, which from the;
Tower ofTie«»e downwards, fall into the faid Chanel i to wit,
thofe of the Sluices q(Goroy and the Drains, of the Meadows of
¥errara: Ai^J moreover, the damages that would arife unto the
faid Iflet of S. Giorgio^ and the Valleys of Comachto^ by the wa-
ters that fliould enter into the Goro or Dam of the Mills of B^//v-
gnardo^ thorow the Trenches of Ojtadrea^yJciich cannot be ftopt,
becaufe they belong to the Duke of Modcna^ who hath right of
diverting the waters of that place at his pleafure to the work of
turning Mills.

The greater part of which Ob)e£^ions, others pretend to prove
frivolous , by faying^ that its running there till at the laft it was
turned another way, is a fign that it had made fuch an eleva4:ion
of the Line, of its Bed as it required^ denying that it needeih
fo great a declivity as is mentioned above , and that for' the fu-
ture it woiild rife no more.

That the faid Dra ns and Ditches did. empty into the fame,
whilft Vo was there ^ fo that they muft needs be more able to do
fo when onely Keno runs that way.

That there would no Breaches follow , or if they did, they
would be onely ofthe water of Ka7/(?, which in few hours might
be taken away (in thofe parts they call damming up of Breaches,
and mending the Bank, r^^///^ ^M?^^^/^ei>Ve4c/?^/) audits a que-
ftion whether they would procure more inconvenience than bene-
fit, for that its Mud and Sand might in many places , by filling
them up, occafion a feafonable improvement.

Now omitting todifcourfe of thefolidity of the reafons on the
ofi^fide, or on the other, I will produce thofe that inove me to
fulpend my allowance of this defign.

The

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2°K.B. 9,163

Lih.i. Of Running WateiIs.

The fii ft IS) that although I dare not fubfcribe to the opinion
of thofe that require 16. inches Declivity in a mile to Reno, t6
prevent its depofing of Mud ; yet would I not be the Author that
ftiould make a trial of it with fo much hazard, for having to fa-
tisfic my felf in fonie particulars caufcd a Level to be taken of
the Rivers Vamone^ SeniOy and Santerno^ by Berriardirjo Aleottiy
we found that they have niore Declivicjr by much than Artlfts re-
(Juire, as alfo the Kttio hath froiii la Bond de Ghtflieri to the
Chappelof Vigarano^ for in the fpace of four miles its Bottoin-
Line falleth five fdct and five inches. So that I hold it greater
prudence to depend upon that example, thin to go contrary tok
common opinion, cfpecially fincc,that the efFcfis caufed by Kem
it felf do confirm me in the fame, for when it was forfaken by.
the Pi?, after a few years, either becaufe it had choaked up its
Chanel with Sand, 6t becaufe its t6o long journey did increafe
it, it alfo naturally turned afide, and took the way of the faid
Pa towards Stellata. Nay, in thofe very years that it did run that
way) it only began (as relations fay) to make Breaches, an evi-
dent fign that it doth dcpofe Saild, ^nd raife its Bed 5 which
greeth with tHe teffimony of fome that were examined in the
Vifitdtion of the tublique Notary , who found great benefit by
havihg Running Water, and fome kind of paffagc for Boaft?,
and yet neverthelcfs affirm" that it for want of Rannrrtg Water
had made too high Stoppages and Shelfes of Sand j fo that if
it (hould be reftorcd to the Courfe that it forfook, I much fear
that after a flioVt time, if not fuddcnly , it would leave it

105

again.

''Xhe fecond I take from the obfervati'on of what happonecT t6
Tanaro , when with fo great applaufe of the Ferarep^ it was
brought by Cardinal Serra into the faid Chanel of Volana v for
that notwithftanding that it had Running Waters in much grea-
ter abundance than Reno yet in thi^ time that it continued itk
that Chanel it railed its Bed well neer five feet, as is to be fecrt
below the Sluice made by Cardinal Capponi to his new Chanel 5
yea, the foid Cardinal Serra who defircd" that this his undertaking
fliould appear to have been of no danger nor damage, was coh-
ftrained at its Overflowings^ to give it Vent into Sanmartind^ thaft
it might not break in upon, and prejudice the City j, vvhichf dan-
ger 1 fliould more fear (vomRcna, in regard it carrittb a' greitfcr
abundance of Water and Sand. ^

. Thirdly, I am much troubled (in the u'ncertaintiy of the fiJe-
oefs of the affair) at the great expence thereto required v For in
regard I do not approve of letting it in, neer to the Fortreffcj
for many refpefts, and carrying it by UTerrc del faiids to thfe.
Umh clg f4irfii it tvill take up eight mfeof dbfabfe Batik^'X

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2°K.B. 9,163

Of the M E N S U R A?T I O N. Lth. 7i

thingj Hot cafie.tP; be procured, by reafojt). that the Grounds lie
under Water i but from the Mouth dcMafi unto Codigoro^ .it
Would alfo be neceflary to make new Scowrings of, the CJiauqJ^
to the end, that the Water approaching :( by wearing and carry-
ing away the Earth on both/hores, might make a. Bed fufficicqt
for ita Body, the depth made for Pa?2dro not ferving- the turn, as
Icop^ceive, and if it Ihould.fufficc, when could the ^people of
Ferrofa hope ta ,be re-irabur(iec^ a;iidj; f^j;i^e4.\f9fi j the cba^
there<i(.?^^^ • ;i:-af:-: m .-j/. ; . . • r'/r

Eourthlyy k|c^v^s as an j^rgument .with me, to -fee that the
very individual perfpns concerned in the Remotion or Diverfion
of j^iejiitd TorrenCtpamely, ^he B^^^ inQline unto it,

and that the whole, City of F^f^r^r^, even tbofe very perfons who
at prefcnt receive, damage by it, cannot indure to hear thereof.
Ther^afpn that indpceth theie laft named to be fo a\(ei:fe thereto,
is, either becaufe that this undertaking will render the introdudi^

of the Water of Main-^o mo;e difficult ^ or becaufe they fear
theq^ngerthereof 5 The others decline the Pro)eft, cither for
that . tjiey know that K.e«(7 cannot long continue in that Courfe,
Pt; b,^f^ufe they fear that it is too much expofed to thofe mens re*
yi^ngfljL^l^Cutting of it who do not defire it fliould i and if a
inap ^avc any other waycs, he ought, in my opinion, to forbear
that^ which to fuchasftand in need of its Removal, isleffe fatit
fafioty, jind tofuchas oppofeit, more prejudicial.

Tp conclude, I exceedingly honour the judgment of Cardinal
vufho having to his Natural Ability and Prudence added
a particular Study, Observation, and Experience of thcfe Wa-
ters jFc|t the fpace of three years together, doth not think tha't
Re/^acango by Volana\ to which agreeth the opinion of Car-
4ipal S. M^/mi/d?3 Legate of this City, of whom, for his exqui-
iite; pnderftanding, we ought to make great account. But if e-
ycrit^ ihould be refolvedon, it would be materially neceffary
rp unite the Quick and Running Waters of the little Chanel of
(\mg;i^o{ the Chanel bia<z/ilioy of Gua^^^aloca^ and at its very
beg^ijCig thofe pf QardagMay which at prefenr, is one of the
Springs or Heads of Panaro^ that fo they might afllft it in carry-
ing its Sand, and the matter of its Muddinefs into the Sea i and
then there would not feil to be a greater evacuatit)n and fcowr-
ijig 9 but withall the Proprietors in the Iflet of San Giorgio and
of Ferrara mull prepare themfelves to indure the inconveniences
of 'Purlings or Sewings of the Water from the River thorow
the Boggy Ground thereabouts.

: I flio.idd nwre eafily incline therefore to carry it into Main'?o
*^ «Sfe//</t^, for the Reafons that Cardinal Capponi moft ingeni-
<^fly eauimerates in a fliort, but well-grounded Traft of his : not

becaufe

Lib.i. (7/ Running Waters.

bccaufe that indeed it would not both by Purlings and by Brea-
ches occafion fome inconvehience ; efpecially, in the beginning :
but bccaufe I hold this for the incomoditics of it, to be a far Icfs
evil than any of the rell h and becaufe thatby this means there is
no occafion given to them of Ferr^r^, to explain that they are
deprived of the hope of ever feeing the ?o again under the Walls
of their City : To whom, vvhere it may be done, it is but reafon
that fatisfaftion (hould be given.

It is certain that Pa was placed by Nature in the midft of this
greatValley made by they^/?;>e;//;i//^ Hills, and by the Alps, to
carry, as the Mafter-Drain to the Sea, that is the grand receptacle
of all Waters •, thofe particular ftreams which defcend from
them. * ,

That the K e«a by all Geographers, ^^r/z^a, fliny , Solimas^
Mella-, and others is enumerated among t\k Rivers that fall into
the faid ?o.

That although Po (liould of it felf change its courfe, yet would
Jieno go to look it out, if the works erefted by humane ind uftry
did not obftrufl: its pafTage j fo that ii neither is, nor ought to
fccm ftrange, if one for. the greater common good fliould turn it
into the fame.

Now at Stellata it may go feveral waies inio Vo , as appeareth
by the levels that were taken by my Order j of all which 1 fliould
beft like the turning of it to la Botta dc Ghiflieri , carrying it
above ]5ondeno to the Church of Gamharone , or a little higher or
lower , as (ball be judged leaft prejudicial, when rt cometh to the
execution, and this for two principal reafons : The one becaufe
that then it will run along by the Confines of the ChurCh P trt-
mony, without (eparating )^errara fiom the reft of it ^ The other
is , Becaufe the Line is (hortcr, and cdnfequently the fall greater^
for that in a fpacc of ten miles and one third, it falleth twenty fix
feet, more by much than is required by Artifts j and would go
by places where it could do but little hurt, notwithftanding that
the peiibns interreflcd ftudy to amplifie it incredibly.

(5n the contrary, there arebut onely two objeftions that afe
worthy to be examined ^ One, That the Drains and Ditches qf
S. of the Chanel of Ce/i/c?, and of B«rzi«^, and all thofc

others that enter into Pt^, do hinder this diverfion of by tbt
encreafing of the waters in the Pi?, The other h that Po lifmg
about the Tranfom of the P/Z^jJcr- Sluice,. Very near ao feet, the
Kefto would have no fall into the fame ^ whereupon it would rife
to a terrible height, at which it would not be poflible to iifiake, or
keep the Banks made , fo that it wOuld break outand di-oWn
the Meadowps, and caufe mifchiefe, and' damages unfpeakabA?
and irreparable , as is evideat by the experiment oladc MP<^

P p p p 2 tarn-

107

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2°K.B. 9,163

Offi^^ Mens u R A T I ON Lib.^.

fdnaro ^yjvhich being confined between Banks , that it might go
into Pa, this not being neither in its greatcft excrefcenfe, it broke
out into the territories of F/W, and of Ferrara. And though
that might be done, it would thereupon enfue , that there being
let into the Chanel of Pa, nioo. fquare feet of water (for fo much
we account thofe of Reno and ?anaro^ taken together in their
gi-cat^ft heights) the fuperficies of it would rife at leaft four feet,
infomuch that either it would be requifite to raife its Banks all the
way unto the Sea, to the fame height, which the treafures of the
Indies would not fuffice to efFeft h or elfe there would be a necef-
fity of enduring exceffive Breaches. To thele two Heads are the
/Arguments reduced, which are largely amplified againft our opi-
nion 5 and I fhall anfwer firft to the laft, as moft material.

I fay therefore 5 that there are three cafes to be con fidered ;
Firft , Pa high , and Reno low. Secondly, Reno high , and ?o
low. Thirdly, Reno and Pa both high together.

Asto the firft and fecond, there is no difficulty in them > for if
P<?ftallnotbeat itsgrcateft height, Re«a (hall ever have a fall
intoit and there (hall need no humane Artifice about the Banks:
AndifRe»aifliaUbclo'V,Pa fliall regurgitate and flow up into
the Chanel of it 5 andalfo from thence no inconvenience (hall
follow^ . The third remains , from which there are expeSed ma-
ny mifchiefsi but it is a moft undoubted truth,that the excrefcen-
cies of Re;/a,as coming from the adjacent Appemines and Rain$,
are toxontinue but feven, or eight hours at moft, and fo would
never 3 or very j^rcly happen to be ai the fame time with thofe of
?0j caufed by the melting of the fnowes of the Alps, at leaft 400*
miles diftance from thence. But becaufe it fometimcs may hap*
^n, I reply, that when it Cometh to pafs^Kewa (hall not go into
Po, but it fliall have allowed it one or two Vents ^ namely, into
the Chanel of Ferrara^ as it hath ever had j and into Sanmarttna^
where it runneth at prefent, and wherewith there is no doubt,bui:
that the pcrfons concerned will be well pleafed , it being a great
benefit to them, to have the water over-flow their grounds once
every four or five years, inftead of feeing it anoy them continu*^
ally. Yea, the Vent may be regulated, referving for it the Cba-
nelin which Re«a at prefent runneth ^ and inftead of turning i|j
by a Dam at la Betta de Ghijlicri^ perliaps, to turn it by help of
ftfong Sluices, that may upon all occafions be opdnedand ftut.
And for my part , I do not queftion but that the Proprietors
themfelves in S'tf»w4rt/;z^t would make a Chanel for it j which
receiving, and confining it in the time of the Vents, might carry
the Sand into the Pa of frimaro : Nor need there thence be fear-
ed «iny ftoppage by Mud and Sand, fince that it i^ fuppofed that
there WVVbut very feldom be any neccflity of ufing itj fo that

LihX. 0/ Running Waters. 109

time would be allowed , upon occafion , to fcowr ind cleanfe

And in this manner all tliofe Prodigies vanifli that are raifcd
with fo much tear from .the enterance of the Water of Kene
fwelled into when it is high, to which there needeth no other
anfwer yet nevertheleffe we do not take that quantity of Wa-
tei^that is carried by Keno^^ad by Pandro, to be fo great as is affir-
med : For that P. D. Benedetto Cafielli hath no lefTe aocutely
than accurately obferved the meafures of this kind, noting that
the breadth and depth of a River is not enough to refolve the
queftion truly, but that there is rcfpeft to b^had to the velocity
df the Waters, and the term of time, things hitherto not confi-
dered by the Skilful in thefe affairs j and therefore they aic not
able to fay what quantity of Waters the faid Rivers carry, nor
to conclude of the riitngs that will follow thereupon. Nay, k
*s moft certain, that if all the Rivers that fall into Poy which are
above thirty, fliould rife at the rate that thefe compute Keno to
do an hundred feet of Banks would not luffice, and yet they
have far fewer : So that this confirmcs the Rule of R. P. D. B<r»e.
detto, namely, that the proportion of the height of the Water
of Reno in Rc/fc^ to the height of the Water of Keno in fo, is
compounded of the proportion of the breadth of the Chanel of
r(?tothatof Keno, and of the velocity of the Water of Rena
in Po to the velccity of the Water of Reno in Reno a mantfeft
Iraument that there cannot in it, by this new augmentation of
Waters follow any alteration that neceQltates the raifing of its
Banks, as appeareth by the example of P4/^r/?.wJ^ ^li
fo far from iwelling P., that it hath rather affwaged it, foc it hath
carried away many Shelfs and many iQets that had grown m its
Bed for want of Waters fuflficient to bear away the matter of
Land-floodsinfobroadaChaneU and as is learnt by the trial
made by us in ?anaro with the Water of Bnrana tor erefting
in the River ftanding marks, and (hutting the laid Sluice,we could
fee no fenfible abatement, nor much lets after we had opened it
fenfible increafment j by which we judge that the fame is to fuc
ceed to ?o, by letting in of Keno, Bnrana having greater pro-
portion to Fanaro than Kcno to ?o, confidenng the ftate of thofe
Rivers in which the Obfervation was made. So that there h no
longer any occafion for thofe great raifings of Banks, and the
danger of the ruptures as well of Ken^ as of Po do vanifti, asal-
fo the fear left that the Sluices which empty into Vo fliould re-
ceive obftruaion : which if they fliould, yet it would be over to
a few hours. And as to the Breaches of ?attaro which happened
in 1 6 2 3 . 1 know not why , feeing that it is confefled that the W
was not, at that time, ^ its height, one fcould rathei char^ ^■t ,

witb

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Of thi M E N 5 u R A 1 1 o 1^ Lik z >

\\'iih the crime, than quit it thereof. The truth is, that the
Bank was not made of proof, fince that the lame now continu-
cth whole ^nd good, and Yatiaro doth not break out 9 nay^ihere
was5when it brake more than a foot and half of its Danks above
the Water, andtofpare , but it broke thorow by a Moles ww-
king^ or by the hole of a Water-Rat, or Tome fuch vermine i
and by occafion of the badncfs of the faid Banks, as I finde by
the teftimony of fdme witneffcs examined by my command,that
I might know the truth thereof. Nor can 1 here forbear to fay,
that it would be better, if in fuch matters men were more candid
andfincere. But tb fecure dur fclvcs neverihelcfl'c, to the ut-
moft of oar power, from fuch like Breaches which may happen
atthefii ft, by reafon of the newneife of the Banks, I prefuppofe
that from ?o unto the place whence Keno is cut, there ought to
be a high and thick Fence made with its Banks, fo that there
Wduldbe nocaufe to fear- any whatfoevcr acceffions of Water,
although that concurrence of three Rivers , which was by fome
more ingenioufly aggravated than faithfully ftated by that which
was faid above were true ^ to whom I think not my felf bound
to make any farther reply, neither to thofe who fay that Fo will
afcend upwards into Re»<?,fince that thefe are the fame perfons
tvho would introduce a fmall branch of the faid ?o into the
Chanel o( Ferrara^ that fo it may conveigh to the Sea, not Reno
bnely, but alfo all the other Brooks of which we complained i
and becaufe that withal it is impoflible,that a River fo capacious
as Po (Kould be incommoded by a Torrents that, as I may fay,
hath no proportion to it.

I come now to the bufineffe of the Ditches and Draines , and
as to the Conveyance of Bnrana^ it hath heretofore been deba-
ted to turn it into Mdin-Fo^ fo that in this cafe it will receive no
harm, and though it were not removed, yet would it by a Trench
under ground purfuc the courfe that it now holdech, and alfo
would be able to dif-imbogue again into the faid new Chanel of
Reno^ which confotming to the fuperficies of the Water of Po^
would continue at a lower level than that which Fanara had
when it cafne to Ferrara^ into which Burana did neverfheleffe
empty it felf for fome time.

The Conveyance or Drain of Santa %ianca^ and the little
Chanel of Cento may alfo empty themfelves by two fubterranean
Trenches, without any prejudice where they run at prefent, or
without any more works of that nature, they may be turned into
the faid new Chanel, although with fomewhat more of incon-
venience V and withall, the Chanel of ferrara^ left dry, would

a fufficient receptacle for any other Sewer or Draio whatfoe-
Vcr, tW fliould remain there.

Air

Lib.

Of R u

NN I NO

A T E RS.

lie

All which Operations might be brought to perfeaion with
150. thoufand Crowns, well and faithfully laid outi whichfumtn
the Bo/c^s^i' will not be unwilling to provide; befides that thofe
Ferrarefi ought to contribute to it , who fliall partake jh,e.

benefit. r i - l- l r

Let me be permitted in this place to propole a thing which!

have thought of, and which pcradventure might oqcafipn two
benefits at once, although it be not wholly new. It Wjp. in th?L
time of ?ofc?dHl V. propounded by one Crefceifx^io ^a
neer to cut the Maia-?Oi above le Ptfpoxxe i and having, made a
fufficient evacuation to derive the water thereof into the ?o of
Adriano and fo to procure it to be Navigable , which was not at
that time efFefted, either by reafono£ the opppfitioas tJ^ofe^
wliofepoffeflionswerc tobe^«<t thorow , or^y reafpii. o^the
great fumof moncy that was neceffary for the efteaingof it :,Bui;
in viewing thofe Rivers, we have obfcrved, thit,the fedg^.cutiin^
might eafily be made below le ? a.fo-i.i.e^\sx digging thqjf^w the^
Bank czWcd. Santa MarUiSc drawiiig a Trench of the bigg^,thafi
skilful Arrifts fliall judge meet uHtb the Ptf » of ;^rwB(>,%lp]fv tli^
Secche ofthefaid S. M4>-ft« i which as being a work, pf. .. ,nc^
above 160; Perches in length , would be fimflied w^li,fi>^eljf
la'oco. Crowns. . ij[(/o-.v fiq*

Firft; it is to^ be believed, that the waters mnning 01*1; Wi^/^
would not fail to open that Moathinto. the Sea, whicl^ ^;Er?j
fent is almoft choakt tip by the Shelfof Sand, ^hich tbfi .fiew
^^Mh of Fonto Vino hnh brought thither and that it wou)4
again bring into ule the Port Goyo^.tad tt^imYi^'ion, ,

And haply experience might teach u,, that flic fuperficies of

mieht come to fall by this affwagement of Water, fo that the
Lceflion of P^eno would queftionlefs make nonfingmit:
Whereupon, if it ftiould fofall out, thofe Princes would have
^ reafon to complain ; who feem to queftioii left by this nev.
acceflionofwaterintoP^the Sluices might be endangered.
Which I thought not fit to omit to reprefcnt to your Lordflijp ;
not that I propofe it to you as a thing abtolutely certain, but that
you'might;ifyoufopleafed,lay it before perfons whofe ,udge-
inents are approved in thefe affairs. ,„ . ....

1 return now from where Idegreft, andaflirm il as mdiibita-
ble thaiRt»? neither can, nor ought to continue longer where
it at this day is ■■> and that it cannot go into any other place but
t\y^t,v,Knhtv Cardinal Caf pom defigned to carry it, and which
at prefent pleafcth me better than any other or into Volana,
whence it was taken away •, the vigilance of Men being able to
obviate part of thofe mifchiefs,which it may do there.

Rut from its Removal, befides the alleviation of the hf^,

112

Of the MlNSURAT ION

Lib I.

v^rhich by it felf is caufcd, there would alio refult the diminution
of that whidi isoccafiOned by the other Brooks, to the right hand
of the Fo oi Argcntajomtvavichzs the faid Po wanting all the
water of Rf/w.itwbuldofneceflity come to ebb in fuch man-
ner, that the Valleys would have a greater Fall into the fame,
and confequently it would take in, and fwallow greater abun-
dance of water ; and by this means the Ditches and Draines
of the Up-Lands would likewife more eafily Fall into them ; cf-
pecially if the fcouring of Zeai^alino were brought to perfedion,
by which the waters ofMarrara would fall into MarmoHa : And
ifalfo that of Brf^M were enlarged, and finiflied, by which there
might enter as much water into the faid Po of Argent as is taken
from it by the removal of Re»o -, although that by that meancs
the water of the Valleys would aiTwage double: Nor would the
people of Argettta,thc iQes of S. Giorgio, and Comatchi„ have any
caule to complain ifor that there would not be given to them
more water than was taken away : Nay fometimes whereas they
had Muddy waters, they vVould have clear ; nor need they to fear
anyrifing: And furthermore, by this means a very great quan-
tity of ground wbuld be reftored to culture •■, For the cfFeaing of
all which, the fumm of $o. thoufand Crowns would go very far,
and would ferve the turn at ptcfent touching thofe Brooks, car-
rybe them a little farther in the mean time, to fill up the greater
<avities of the Valleys, that we might not enter upon a vafter
and harder work, that would bring with it the difficulties ot other
operations, *nd Co would hinder the benefit which thcic people
expeftfrom the paternal charity of His Holincfs.

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Lib.i.

T O

The Right Honourable,

MONSIGNORE
D. Ferrante Cefarini.

Y Trcatife of the M e n s u r a t i o n of R u n-
N I N G W A T E R S5 Right Hoiiourable^ and
moft Noble Sir, hath not a greater Preroga-
Uve than its having been the produftion of the
command of Pope Z^r^^/ Vlll.when HisHo-
linefswas plealed to enjoyn me to go with
Moiifigndrc Corfini^ in the Vifitation . that was
impofed upon him in the year 1625. of the Waters of F^rrara^
hologna^ Kowagna^ znd Komagfiola/yfot that , on that occalion
applying my whole Study to my icrvice and duty, I publifhed in
ihatTieatile iomc particulars till then not rightly undcr/lood and
confide- cd (f that 1 knew) by any one ^ although they be in them-
fclvcs moft important, and of extraordinary confequence. Yet
I m lift rcrdcr thanks to Your Lordfhip for the honour you have
done to that my Traft , but wifli withal, that your Efteem of it
may not prejudice the univcrfalEftecm that the World hath of
Your Honours moft refined judgement.

As to that Point which 1 touch upon in the Conclufion, name-
ly,Thac the confidcration of the Velocity of Running Water fup-
plyeththeconfideration of the * Length omitted in the common
way oi mcat'uring Panning Waters^ Your Lordfliip having com-
manded me that in favour oiFratiife^ and for the perfeft difco-
very of the diforder that commonly happencth now adayes in
thediftributionof the Waters of Fountains, I fliould demon-
ftrate that, the knowledge of the Velocity ferveth for the finding
of the Length : I have thought fit to fatisfie your Command by
relating a Fable ^ which, if I do not deceive my felf, will mak^
out to us thet»^tith thereof infomuch that the reft of my Treatifc
(hall thereBy alfo become more manifeft and intelligible , ev^n to

Q-llq thofe

* Larghe22a,bu?;
mifprimcd.

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0/;/;<? MENSURATION

thofe who finde therein lome kinde of obfcuiity.

In the dayes of yore, before that the admirable Art ot Wea-
ving was in ufe, there was found in Ptrfia a vaftand unvaluable
Treafure which confifted in an huge multitude ot pieces of Er-
mefin, or' Damask, 1 know not whether ^ which , as I t^ike 't,
amounted to near two thoufand pieces ; which were ot Inch a
nature, that though their Breadth and Thicknefs were finite and
determinate, as they ufe to be at this day ; yet neverthelels, their
Length was in a certain fenfe infinite, for that thofe two thoufand
pieces, day and night without ceafing,i{rued out with their ends
at fuch a rate, that of each piece there ilVued loo. Ells a day,from
a deep and dark Cave, confccratcd by the Superftition ot thole
people, to the hbnlo'-ii, Arachne. In thofe innocent and early
times '( I take it to have been, in that fo much applauded and
defired Golden age J) it was left to the liberty of any one, to cut
off of thofe pieces what quantity they pleafed without any diffi-
culty : But that felicity decaying and degenerating, which was
altogether ignorant ofMeum and T«kw •, terms certainly molt
pernicious, the Original of all evils, andcaufe of all difcordsj
there were by thofe people ftrong and vigiiant Guards placed
upon the Cave, who refolvcd to make merchandize of the Stuftesj
and in this manner they began to (eta price upon that ineftima-
ble Treafure, felling the propriety in thofe pieces to divers Mer-
chants ; to fome they fold a right in one, to lome in two , and to
fome in more. But that which was the worft of all, There was
found out by the infatiable avarice of thefe men crafty inventions
to deceive the Merchants alio j who came to buy the atorefaid
commodity , and to make themfelves Mailers , fome of one
fome of two , and fome of more ends of thofe pieces of fluff j
and in particular, there were certain ingenuous Machines placed
in the more fecret places of the Cave, with which at the pleafure
of the Guards, they did retard the velocity of thofe Stuffs, in
their iffuing out of the Cave; infomuch,that he who ought to have
had 100. Ellsof Stuffin a day,had not above 50, and he who
ihould have had 400, enjoyed the benefit of 50. onely •, and fo all
the reft were defrauded of their Rights,the furplufage being fold,
appropriated, and (harcd at the will of the corrupt Officers : So
that the bufinefs was without all order or juftice , infomuch that
theGoddefs y<i"<i<:/)«e being difpleafcd at thofe people, deprived
every one of their benefit, and with a fireadful Earthquake for
ever clofing the mouth of the Gave, in punifhment of fo much
impiety and malice : Nor did it avail them to excufe themfelves,
by faying that they allowed the Buyer the Breadth and Thick-
nets bargained for ; and that of the Length, which was infinite,
° there

0/ R. U N N I N G W A T E H S.

there could no account be kept : For the wife and prudent
Pfieft of the Sacred Grotto anfwercd, That the deceit lay in the
length, which rhey were defrauded of, in that the velocity of the?
ftutfe was retarded, * as it ilTued out of the Caive : and although
the total length of the Piece was infimte, for that it never cca-
fed coming forth, and fo was not to be computed ; yet nevcr-
thelefs its length confidered, part by part, as it came out of the
Cjive, and was bargained for, continued ftill finite , and might
be one while greater, and another while leffer, according as the
Piece was conftituted in greater or le^^er velocity* j and he added
wichall, that exaftjufticc required, that when they fold a pieCe
of fluff, and the propriety or dominion therein, they ought not
only to have afcertained the breadth and thickneffe of the Pieces
but alfo to have detcrmiii^^ tbc length, determining its ve-

^^^Ihz f^tt^- diforder and confufion, that was reprefented in the
Fable, doth come to palTein the Hiftory of the Diftribution of
the Waters of Conduits and Fountains, feeing that they are fold
and bought, having regard Only to the two Dimenfions, I mean
of Breadth and Height of the Mouth that difchargeth the Wa-
ter \ and to remedy fuch an inconveniq^e, it is neceffary to de-
termine the length in the velocity ; for never flball we be able tq^
riiakeagueffeatthe quantity of the Body of Running Water,
with the two Dimcnfionsonly of Breadth and Height, without

^^And to the end^ that the whole bufincfs may be reduced
ro a mofl cade praaicc, by which the vratcrs of Aquedua*
may be bought and fold jiiftly, ^nd withmeaiurcs alwayes ex^
aftandconftant. .

Firft the quantity of the Water ought diligently to be exa*
mined, 'which the whole principal ; Pipe difchargeth in a. time
certain, as for inftance, in an holir, m half ^ hour, |r in a leflfc
interval of time, (for knowing which I havet moff cxaS and
eafie Rule) and finding that the whole prmcipal pipe difchar-
^etlt^ fr, a thouiand tuns of Water in the fpace of one or
more hours, in felling of this water^ it ought not to be uttered by
the ordinary and falfe meafure, but the diftribution is to be
-made with agreement to give ;tnd maintain to the buyer ten cr
twenty, or a greater number of Turis, as the bargain (hall be
made, in the fpace of an htfur, or of fome other fct and dete^
minate time. And here I adde, tliat if 1 were to undertake to^
make fucb ah ad>uftment, 1 would make ufe of a way to divide
and meafure the time with fuch accuratencffe, that the fpace of
art hoiir fhbuld be divided into four, fix, or eight thoufand par|8

Ctq qq i «^t»"

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Ll6

Of the M E K S U R A T i O M. Lik 7.

without the leaft errour which Rule was taught luc by my
Maftcr ^Si^w. GaliUo GaliUi^ Chief Fhiloibpher to the moft Se-
rene Grand Dnke ofTufcany. And this way will ferve cafily and
admirably to our purpole and occaiion fo that vvc fliall
thereby be able to know-how many ()iiarts of Water an A-
qiieduft will difcharge in a given time of hours, moneths, or
years. And in this manner we may conftitute a Cock that fliall
difcharge a certain and determinate quantity of water in a time'

given. •

And becaufe-daily experience fliews us, that the Springs of A-
queduflsdo not maintain them alwayes equally high, and full
of Water, but that fometimes they increafe, and fometimes de-
creafe, which accident might poffibly procure fome difficulty in
our diftribution : Therefore, to the end that all manner of fcru-
ple may be removed, 1 conceive that it would be convenient to
provide a Ciftern, according to the occaiion, into which there
inight alwayes fall Qni2 certain quantity of water, which fliould
not be .greater than that which the principal pipe diichargeth in
times of drought, when the Springs are bare of water, that fo in
this Ciftern the water might alwayes keep at one conftant height.
Then to the Ciftern fo jprepared we are to faften the Cocks of
particular pcrfonSj tQ wlfom the Water is fold by the Reverend
Apoftolique Charfiber, according to what hath been obferved
before, and that quantity of .Water which rcmaineth over and
above, is to be difcharged into another Ciftern, in which the
Cockuof ,the WaJters for publick fervices, and of thofe which
people buy upon particular occafions arc to be placed. And
when the bp fincife fliall have been brought to this paffe, there
willlikewife a remedy be founH to the fo many diior^ers that
contiimally happen b of which, for brevity fake, 1 vvill inftance
in but four pnly^ which concern both publiquc and private bene-
fit, as bein^ in,jp&)(^udgment, the moft enormous and intole-

The firft inconvenience is, that i|i the common way of meafu-
ring, difpenfiag,^ and felling the Waters of Aquedufts, it is not
underftood, neither by the Buyer nor Seller, what the quantity
truly is that is bought and fold j nor could I ever meet with any
cither Engineer pr Architeft, or Artift, or other that was able to
dtcypher to me, what one, or two, or ten inches of water was.
But by wr above declared Rule, for difpenfing the Waters of
Aquedufls we may very cafily know the true quantity of Water
that isc bought , or fold, as that it is fo many Tuns an hour, fo ma-
ny a day t lb many in a year, &c. .
The feconddifordertkat happeneth, at pfefent, ip the diftri-

buting

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Lih. 3. Of R il iiNI KG VV A t:E RS.

bution of Aquedufts is, that as the bufinelTe is-jiow ,g^v*}^ijp4i5
llcth in the power of a lor did Mafon to take an jaftlyifo/p^q^
and give undefervedly to another more or ielk ; Water. .fh^j^,^
lonelth to them of right : Anfl I have ftco it; ,!%i,^;flfoi?a
own experience. But in our way of mealuring and diftn-
buting Waters, there can no fraud be copimitted ■■, and put-
^ine the cafe that they ftiould be committed, its an eafie mat-
ter to know it , and amend it , by repairing to the Tribunal

^'''^Thirdly, it happens very often,(and we have examples there-
of both antient and modern) that in difpenfing the Water after
the common and vulgar way i there is fometimes mqre Water dif-
pended than there isln the Regifter,-ht^fffich there will be rcgi-
Led, as they fay, two hundred inches (for example) apd there
will be difpenfed two hundred and fitty inches, or more. Which
paffaae happened in the time of Ner'va the Emperour, as Giulio
froniino writes, in his 2- Book, De Aiuadnmbm Z>rbis Komx,
where he obferveth that they had mC«mwentariji i2y<^<. Qui.
naries of Wztct i and found that they difpenfed 14018
naries And the like Errour hath continued, and is in ule alio
modcrnly until our tirries. But if our Rule fliall be obferved,
we fliall incur no fach diforder, nay there will alwayes be given
to every one his (hare, according to the holy end of exaft juftice,
which dat umcniqne qnodfuHm eji. As on the contrary it is
manifeft, that His Divine Majefty hateth and abommateth
dHS&pondm Menfura & mnfura, as the Holy Ghoil Ipeak-
ethby the m6uth of Solomon in the Proverbs, Chap.^o. Pondus
eh. ?ond,0, MMnra ^ Menfura, ummq.ic abominahh cfi afud
Denm And therefore who is it that feeth not that the way of
dividingandmeafuringof Waters commonly uied, is exprefly
aaainft the Law of God. Since that thereoy the ^-"J^ -"^^ "JP,
is made fometimes greater, and fometimeslefferi A <Jiforde fo
enormous and execrable,that I flrall take the bol^lnef^ to fay that
for this fole rcfpea it ought to be condemned and prohibited like-
wife by human Law,which fliouldEnaa that in thls^ufinefs there .
(hould be imployed either this our Rule or fome other that
is more exquifite and pradicable , whereby the meafure
might keep one conftant and determinate tenor, as we make it,
and not, as it is now, to make Pondu, &Pondus, Menfura &

*^ A^d'this is all that I had to offer to Your moft Illuftrio,^s
Lordfliip, in obedience to your commands, referving to my lelf
the giving of a more exaa account of this my iiivcntion, whflP
tTie occafion (hall offer, of reducing to ptaaice fo holy, )ufl:, an^

Of fl&* M E MSU RATION Ub.t:
neceffary a reformation of thcMeafure of Running Waters and
of Aqucdufis in particular : which Rule may alio be of great
benefit in the divifion of the greater Waters to over-flow
Ctounds, and for other ufes: 1 humbly bow,

Yom Mofl Devoted,
and

Mff^ Obliged ServuBS,

■ ■ D.Benedetto Caftelli, A^iC/ft.

FINIS.

ABatements of 4 River in different and unequal Diverfimt , is tdmiei equaf,
which is proved » ith i oo. Syphons. P^S^^ 75

Arno River when ttrifethupoa^i^and-FloodneartheSe^ on$ third of a Brace^ it
rifeth aim^ Pi^^ -j.Btmcs. 82

Banks near tQ the Sea Imer, ^an far from thence. CsroUarj XIV. 16

Brent River diverted from the Lake o{ Veniee, and its effeBs. 6^
Brent fuppofedinfufficient to remedy the inconveniencejof the LakeyOftd the falfitjof that

fuppoption. ^7

Brent, andits henefitsin the Lake. ^ _ . ^ 7^

Its DepofitionofSandinthe Lake ^how great ttii. 78,7^

Bridges ffuer Rivers, and how they are to he made, jifpendis VIIl. ao

Burana River, its rifir>gy and falling in Panaro. 1 10

Caftelli applied himf elf to this Study hy Order of Urban VIIL
Chanel of Navigation theralltysof Bologna, anditsincanventeiues.

Carriedinto thePoof^eTTara.dftdits 6e^;efits wd.
Ciampoli aim^er ofthefe Obfirvationsof Waters. 3

DlfHcultiofthuhpnefs of Meafuring Waters. *
Dijorders that happen in the difinbution of the jVaterst^ AqutduSs, ondtheirre-

q)iftrih^tion of the Waters of Vountains, and AqueduBs. Appendix X. 22
qyiftrihutionoff^ater to over^ftoiT Grounds. AppendtxXl. 23, 69^70

Diverfion o/Reno and other Brooks of ^omAgna, advi fed hy P. Spetnaizmtonhatend

Drains a^d Ditches, the benefit they receive hy cutting away the ff^eeds And Reeds.

Appendix IX. . . . « » ,

Drains and Servers obflruBed^ inthe Diverfion of KcnotntoMsLin Poland d remedy for

the fame.

Engineers unverfdin the matters eftVaters. ^ 2

Erour found in the common way of Meaf aring Rnnning tVatersi 68j 69

Errour in deriving the f^ater of AcqOa Paola. Afpendi:^ 1 1. 17*

1 he Table.

Em«r$Vf«^'«"''''«'''^'"*''''*" "'^'^^"f- m ibid.

Errouf^mUr Er.gi«ferS ^ cof,tra,y to tk fnM. .ifyj^.>cAV.. i^il.

eZut of Giulio . Frontino in Mcalurixg th Wmstf s. ^tf^^'

irrmscommittedin lutthg the B»r.k « Bondeno , « tUfrrtUirgs ofYo: CorcH^y

VT1T

XIII.

I'ms Pontine, D/tf/W^) P^?;^? Sixius QurDii35,«r/7Hv?(? ixf ^/^rf.

7le rmne affd mif carriage thereof. . ^ , ^ • ;kf^

rArMtypfthrprir.cifalcha>iei that Vrahs them, caufe if the Lrcwnjr;^^ iDid.
Tj^fV tfr^ h the Ftfkip^J^ ears^nhuk ek tke Rner.

waters of IlumcSmo, Mfion> ingteatslurMtxtimthe^v^cyy^torcfthe

faidreU • If II

RemediestothtdiforderSifthofeFems. 95^^^

Fontana Giovanni, hU errours in Me^^ur'tng mtas. CcrolkryW. 9

riumeMorto, whether it ought tofalUitfitheSea, cr /^.foSerchio, 79

Letinto Setchlq'4K<^JtshcofizeKumes. • 7^'^^

rhedaMeroui rtfinQoJhsyvatirS:«hentoheexp(Bed. j a

On the Sea-eoafts, atfugh time as the winds mde the Sea tofneH. 8 j

Q^\iWQCz\\\x\,hoMurdlj7nentmed, /'^^(Ji^aS
m UUfor meflfuring the time.

Hei£hty\ld&^S^i(k . i j-

Heights difftrem, made lythefamiftrem^a Brotior Torrent , according to the dtvers

Velocities the entrance of the met. CcroVary 1. . f

Hetihts differe^'t, made ly the Torrent in the Rk er, acccrdirg to the digerer.t heights tf

ihcRiz^r. Corollary \L it>id.

Kumleeige Motion h(m i^hitimporteth. ^

Lake cj Thrafmcriis and Ctr.fderatmJ ufcn it^aLeittrwrmcn to Sig.Cm^o

i^** c/ Venice, and Ccifdetaticrsupn it. 75

^wwaterswhiehM dtUtimifithdifco^v . ^ \^

Thefoffageand ckcaking of the Fcrts.amair. caufe (J th difodcrs iftheLalu
And the grand remec.'j to thofe di(ordtts n hat it is.

Lakes and Meets along the Sca^ccap, ard tht caufes thncof.

Length of mters:, htve itisto ie Ideafured. 7®

1 8

MeafmefindiiiprUutimofWattri. ^^ppendipi'V^ ^

1 he Table.

A^.^Cfjr^nf i^h eyi that fall into others difficult. CoreS, ^ 9

; i/j^^^^bmnmci'miitit River ^{Aatft^i^^^i^^^- 48

' 7Jfflf/o/^ ftincipalfuhjcaof Phtltfophj.
i^iw^. Vide

Bologna. r^^cr

) time as

> lOl

\Peruqia, Vidq . , ^ .

'S^3=VeK' Malamocco, Bondoio , Chiczza .f«r «.*^^

Quick-Hcightof Jt/^'r, ,t U. Dffimtm V. • ^

ReafcKs of Monfignore Corfini agatnft tPf « i i
i..WCardinal0.pponi-«^ Monfig. Corfini , for ih. ^»ming .f Reno into

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

The Tabic.

T^o ohje^ions on the contrary , and anftrers tcthem. 1 04 (J^ 105

Wte ought to he the proportion ^of the "Heights ^Rcno in Rciio , and of ^^no in
Po. I 10

Regulator V£>hat it is. Definition IV. 48
Relation of the rvaters of BologniL and Vcvr 3 n , hj Mon/ignore Corfini loc?
•Reno in the Valleys^ and its had ejfeffs, loo, lol

Tivo wayes to divert it. lOJ
The facility and utility of thofe tvayes^ Ibid.
7 he difficulties ohj(^ed, 1 04

Re^ljto Bartolotti touching the dangers of turn' ng Fiume Morto ///^o Serchio. 83
Retardm:nt of the courfe of a River caufed by its Banks. Appendix VII. \9
R'ifings made by Flood-Gatei hut pnall. Appendix X 1 1 1. 26
Rivers that are fallow fi^tll txuch upon [mall fiovrers , fuch as ate deep rife hm little vpQn
great Floods, Corollary III- ^
Rivers the higher they are ^ the fwifter, Ibjj,
Rivers the higher they are , thele^e the} encreaje upon Floods, 49
Rivers vfheK th?y are to ha'^e equal and vphe,. h^e Velocitj , Ibid.
Rivers in faHlg into the Sea , forma dhe/F of Sand called Cavallo. d5
i^ive Rixe* J to h diverted from the lah^f Venice, and the inconveniences thatwould
enfue thereupon,

A Ri'.erof ^;cl;:hfi^ht , and Vilocity in its Regulator heing given, if tht Height
he redoubled by nev fVater , it redsubleth afo in Velocity. Propofiticn I L ihe^
'Ctem L \ J I

Keepeth the propdnion cf the heights , to the Velocities, Corollary 5 ^

Sand and A^ud that entereth into the LaU of Venice , and the tray to examine it, 7^
Setts agitated and driven iy the Winds ficp up the Forts, 5^
Setiio^.s of a River what they are. Definition I,

SeBions equally fhift whatthey are. Definition \l. Ibid,
SeBions of a River being given, to conceive others equal to them , of different hreadth,

height and Ve/ocity, Petition, -g
S€i^icns of tie fame Bi-vtr , ar.d tleir T report ions to their Velocities. CtroU, I. 42
Seasons of a River difeharge in any rthatfoever place of the [aid River , equal quantities

of t^ater in equal times, Propofition \,
Sile River what mifchiefesit threatneth , diverted front the Lake. ^4
^pirtings of Waters grow bigger the hi^er they go, Coroli. XVI. 1$
Sr earns of Rivers how they encreafe and vary. Cor oil, I. ^
Streams retarded ^ and the effe^s thereof , Cmll, IX. ig

ruble of the Heights, Additions, and J^udntities of mttrS , and its ufi. 55

Th.ajimenus. Vide Lake.

Time how its me of wed in thefe Operations of the Waters.

Torrents encreafe at the encreaJingofaRivery though they cart j to mdre Water than before
CoroU. IV. ^ ^

Torrents whentheydepofe and carry away the Sand, CoroU. V. y
Torre tit sand their effjfs in a River. j
Torrents thatfaUim$ the Valleys ^ or ir^oV o of Vohno ^ and their mifchiefs preve/tt-
ed y^hythedii^ertingofRcnointoMainPo. 100
Tyhr and tht cm[esof its imsndations. CoroU. V 1 1 L S

bid.

The Jable:

yaUeyt of Bologna and Ferrara , their inundsuons anA di[order$ , wbme
ceed.

Velocity of the Water jbevn hy feveral Examples^
Its proportion to the Meafun.
f^eUcities equal ^ what thfyare.
Velocities like, what they are.

Velocities of Water known, how they helpm in frJingthe LtK^h>

A Fahle to explain the truth thereof.
Venice. Vide Lake.

Vfe oj the Regulator in meafuring great Rivers. .Confideration I .

Waters f alUng, why the^dif^r op. GorolL XVI. i5

Waters^ how the Length of them is Meafured. 70

Waters that are imployed to Jlow grounds, how they are tohe diflributed. ip, ^3,54

Waters to becanyedin Pipes y to fervt Aquadu^s and Conduits y how they Are to be Mea-

fared. HJ, Ii5

Wd )i to know the rifing of Lakes b)i Raines. 2 8

Way of the Vulgar to Meafure the Waters «f Rivers. 68

windGuny and Tortahle fountain of Vincenzo Vincenti of Urbin. 1 1

tvindes contrary, retard ^ and mah^ Rivtrs encreafe. C trolL VII. 8

The E N D of the T A B L E of the Second Part
of the Firft TOME,

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

Images reproduced by courtesy of the Royal Library, Copenhagen.

2°K.B. 9,163

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Full text of "Mathematical collections and translations, in two tomes, [translat. and ed.] by Thomas Salusbury"

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